Oh, I'm aware that it does help the Alch, but unless you're absolutely spamming the alch, you don't really reap the full benefit (at least not, to the same degree as you would with, say a polaris or blaster), especially since the charge is so viable to use in both PvP and CW. I should probably clarify that I'm not saying to NOT have asi on the alchs, but that I feel that CTR is ultimately more beneficial.

For Lockdown, ASI is obviously the only UV anyone cares about.

For PvE, my opinions:

With Blitz, max ASI versus no ASI is equivalent to about one point of CTR in terms of damage output over time. ASI makes the gun a lot more mobile, but CTR is far and away what you want to max on Blitz.

Alchemers benefit about equally from ASI and CTR. I care about both less than I do about damage, but everything's pretty close.

Antiguas are nice defensive guns that you don't ever really charge because the charge attack is dangerous to use and doesn't tend to deal much damage. They don't benefit much from ASI, either.

Polaris you don't care about CTR, obviously.

I hate Callahan and find it completely unusable.

Blitz: CTR >>> Damage = ASI
Umbra/Nova: Damage > ASI = CTR
Antiguas: Damage >> ASI >>>>> CTR
Polaris: Damage = ASI >>>>> CTR

Other note, gun sets sans Shadowsun provide ASI. Therefore damage UVs are actually useful most of the time on guns, and they're a lot cheaper than ASI/CTR because people don't realize you can just pick up two of the same weapon with two different damage UVs for less than one with ASI/CTR. For example, shadow is used on slimes and gremlins, and you will be wearing Justifier or Nameless against them, so ASI beyond medium on a shadow gun is a tough sell for PvE. Conversely, a VH Undead Polaris is not that useful since you'll be wearing Shadowsun.

ASI:

• Magnii/Magnuses
• Antiguas
• Pulsars
• Valiance
• Catalysers
• Drivers

CTR:

• Autoguns
• Catalysers
• Drivers

In general, most people will not be using the charge attack of the Magnus lines, and even then the recovery is more important than the time taken to charge, since that thing knocks you prone and renders you incapable of movement.
Antigua lines are 'plug-it-with-bullets' style guns just in order to get a decent DPS, and its charge is generally unused since it leaves you temporarily immobile.
Pulsars... are pulsars, nobody is really going to want CTR on these. I only saw someone use the charge once. Oddly enough, it explodes in a similar manner to the Sealed's projectiles when used if your back is against the wall, I have no idea why.
Valiance is also generally used as a fast-firing gun; its charge is a more damaging version of its bullets, but takes more time to prepare. Since this gun is mainly about speed and mobility, and deals normal damage to boot, the charge doesn't really fit in with the reason that most people buy this weapon for.
Catalysers are mainly used for their charge, turning enemies into walking bombs. Personally, I find that the CTR of the weapon at full heat is fast enough, and I would prefer ASI over CTR, but then that's just me, and I can see a valid reason why people would want a CTR bonus on that weapon. Both are fairly desirable.
Drivers are high-damage, especially on their charge attack. It takes some time to complete the reload animation, however, so both CTR and ASI are desirable; CTR slightly more so on the pure-damage drivers, and ASI on the status drivers (since much of the point of the status driver is to spread it around as much as possible, so the high-damage charge isn't as important).
Autogun lines all benefit greatly from CTR, especially since the charge is pretty much all that most people use. ASI does help to speed up the reloading animation, but doesn't have as much of an effect.

Its more important in pvp to have ASI through but in pve DB or CTR are better