One way to look at UVs is to start off by asking yourself: "Well I have a bunch of 5 star items heat 10, how can I make them better? For my armors it is all just a waste of money because I can dodge monster attacks. If it's a weapon, one might say well all damage bonus UVs are worthless, since I can get armor that gives me universal damage bonus. That leaves attack speed increase and charge time reduction, but I almost never charge my weapon, so the only one that is any good is ASI. And I can kind of get that from a swiftstrike buckler already, but if I wanted to I could reach max ASI if I had at least ASI high on my weapon. The chances of getting the UV I want can therefore be easily calculated at 1/8 to get ASI and then perhaps 1/15 to get a High or Very High. At 20k per ticket that will still cost me millions and I might get 'unlucky' and never get the one I want."
The other way to look at UVs might go something like this: "Ok well my gear currently has no variants at all, if I spend 20k crowns once, what can I get from that? I can get a low damage bonus against a monster type, hmm I probably won't notice that much. I might get ASI low or CTR low though, which is +1 on a 6 point scale. I might get damage medium against fiends which I can definitely use on that Barbarous thorn blade I sometimes carry as a side arm for fiend levels because the guns that I usually use are harder to use against fiends. I might get ASI or CTR Medium which will let me swap out a trinket for a health one, giving me +6 health, because even though the pros give me the advice to 'just dodge more', I secretly take a hit every now and then. I might get one of the less common variants like Gremlin High or Undead Very High on my blitz needle. Now I usually kill Undead with my Combuster, but I want to do the Snarbolax Shadow Lair next month and I plan to take my blitz as a side arm, so the undead very high might come in handy for that. For my armors, pretty much any status UV of medium or higher is a nice bonus, it's basically like a status trinket that doesn't take up a slot. A low status UV that matches my armors inherent resistance might make me immune to that status. And if I get a high or max status resistance, it'll expand the usefulness of my armor piece to a whole new set of levels. A medium to max defense variant will probably save me a few pips of health regardless of the mission because I am bound to get hit by something eventually. So whatever it is that I roll on, it is only really low defense UVs for armors and low damage bonus UVs for weapons that I could consider useless, which might be about half of my rolls. But considering the amount that I spent upgrading and heating my gear, spending an extra 40k crowns on each item to get a more or less useful upgrade (potentially game changing in a good portion of those). And now that I am thinking about this, I realize that I can increase my chances of getting something useful by rolling on items that can still be upgraded to several 5 star versions. So from now on, before I craft and fully heat an item to 5 star heat 10, I will try to roll on the 2 star version to try and get a rare variant. Then I will upgrade the weapon into the version that benefits from that type of variant the most."
Turned out longer than expected, but I hope someone finds it useful. I think a lot of the frustration surrounding UVs stems from players tunnel visioning on the 1 or 2 UVs that they deem useful and immediately dismissing any other UV as useless. That is also the mindset that makes players rush to chaos or black kat with a blitz and combuster and then they get upset when a new level is introduced and their one trick playstyle gets shredded by a bunch of mini slimes that kill them dead in 4 hits.
If I understand correctly, there are a couple of ideas hiding in here.
One idea is that getting a weapon to 5 stars takes a lot of resources, and putting another 20,000 crowns into it isn't really that much. So do one Punch, and get a UV that is either slightly helpful or really helpful, and appreciate it for what it is. This view is healthful. Sure.
The other idea is to Punch items early --- at 2 stars, say --- and then decide their upgrade path based on the UV that you get. For example, if you get undead+4 on a 2-star Brandish, then upgrade it to an elemental option rather than a shadow option.
Back in the days of mist energy, a lot of players (myself included) would have multiple accounts, using all of that mist to mass-craft 2-star items, hoping to get good UVs, and upgrading to 3 stars accordingly. In fact, there were complaints that gunners and bombers were disadvantaged, because a lot of their weapon lines (e.g. alchemers) locked you into a particular damage type already at 2 stars. So yes, a lot of players agreed with you.
The problem is that damage bonuses are now so easy to get (Black Kat, Chaos, Barbarous Thorn Shield, etc.) that the monster-specific damage UVs on weapons are close to worthless. And player research suggests that damage UVs on armor and shields do almost nothing. So CTR, ASI, and status UVs are dramatically more valuable than damage UVs. So my advice to players is always:
* If you can buy a great UV from another player (e.g. CTR+4 on a 3-star Dark Briar Barrage or shock+4 on a 2-star Magic Cloak), then buy it and upgrade from there. Congratulations.
* Otherwise, use every one of your craftings to try to get great UVs. For example, if you have a 2-star Brandish with undead+4, don't keep that UV. Throw it out, just for the slim chance of getting CTR or ASI. If you make it to 5 stars without getting any great UVs (which is usually the case), then Punch from there. Or start again at 2 stars with a UV bought from another player.
You are right that there are a few special situations in which weapon damage UVs can be viewed as pretty good --- namely, when you use that weapon only on that one family. For example, fiend+4 on Dark Briar Barrage is good, if you use DBB only on piercing-vulnerable enemies, and you ignore beasts because they're too easy anyway.