Is Damage Resistance That Useless?

I've seen a lot of discussion on these forums about how Chaos is the objectively best armor (which it is) and how statuses are the most dangerous thing to an experience player (which they are in terms of fire and shock) but reading some posts I get the feeling the regulars have come to the conclusion that it's better to take something like Sunset armor for damage than take another gunner line that would protect against said damage. So I ask, is damage resistance that useless in T3 Elite difficulty? That taking an armor with useless special defense for a level for it's offensive bonuses is better than something that would protect against that damage with different offensive bonuses?
Also no, I can't dodge or shield against everything, so not getting hit is not an option, and assuming killing everything before it kills me isn't an option either.

I suppose when you're me with bad internet and a bad computer damage itself tends to be deadlier than statuses. I suppose I could be unusual.
I've read the guide a few times but it seems I've read it and come to the wrong conclusion then. I suppose I'll flip through the pages again, see what I missed.

I'm not sure how the guide led you to the opposite view. It contains statements such as:
"The overall importance of damage protection is not as big as you might expect. Highly protective armor might let you survive one more hit than weakly protective armor."
"In choosing armor, your top priorities should be abilities and status resistance. Which one you favor depends on your experience, lagginess, etc. Damage protection and health are low priorities."
The justification for this opinion of mine is: A bad status effect can lead to multiple hits, which no armor will let you survive. For example, when fighting shock mecha knights, you can stay alive as long as you don't get shocked. As soon as you get shocked, you start taking damage and more shock, and you have a high probability of dying.

Another thing to factor into account are which attacks you tend to get hit with the most.
A lot of people have difficulty dodging devilite attacks. Being able to survive 1 additional attack from devilites may be more important than being able to survive 1 more attack than wolvers or gremlins (which I find much easier to dodge).
That being said (and in agreement with Bopp), choosing the wrong status resists can make 1 hit lethal. Matching damage protection should only be taken into account after status resists and boosts are covered.
While it's a rather difficult read, The Wiki's Defense Page has some information about how damage is calculated. Very weak attacks (such as mini-monsters and range attacks) will be strongly influenced by defense (and may increase that 1 attack metric to 2 or even 3), while very strong attacks (such as Vana's mace) aren't as influenced.

Damage resistance is not useless, it's just that chaos has practically as much damage resistance as gray feather.

Also consider that if a level has multiple damage types you're going to likely be missing one or more. You can't fully cover normal, shadow and elemental and fire in fsc. You can try but defensive armors just aren't defensive enough. Ancient+Divine gets you about as close as vog and black kat at tremendous cost.

I remember that one time in lockdown when me and another guy were weilding a winter grave each and full black kat (my winter grave wasn't fully heated tho) and this guy comes with full black kat and just tanked a full 3 winter grave charges. While I could kill chaos users with only 2 charges. So, no it isn't that useless.
Edit: Oh... just realised this is from last year... /e facepalms.

Even with a double max shadow and dual pentas, it's impossible for a black kat user to survive three shots from winter grave. I offer alternative explanations:
- The other guy was not a striker
- The other guy had picked up a vita pod
- When you say "tanked three shots" you meant "died after the third shot", which is plausible. A full black kat would have 2 pips of health left after 2 winter grave charges.
- Your winter grave was extremely unheated. You do mention it not being fully heated. At level 5, winter grave only has a fraction of its true power.
- You didn't hit 3 times
- 2 of the hits weren't charge attacks
You can try the scenario for yourself in my Lockdown Calculator

My winter grave was level 3, the other guy's wasn't 10 as well I think, the guy we attacked was a striker, all the shots were charges. There are no vitas in LD.

Alright, level 3 is very low, so that explains it. Your gun is currently much weaker than if you'd left it at 4*.
By the way, Chaos users will also survive at least two charges of a fully heated max damage Winter Grave (with 1 + 1/4 pip of health remaining, or 48 HP), so either whoever you've been shooting did not have dual pentas, have taken damage beforehand, or were deathmarked in advance.
You can find vitas in LD because sometimes there are PvE enemies, and people have found vitas from them in Lockdown.
I heard Lichens were dropping vitapods only during the first Hardcore Mode. But I don't play Lockdown so I could be wrong.

Most of my time in this game is spent in LD and I can tell you I've never seen a vitapod or someone who got a vitapod in LD. Not the stone slimes, not the lichens, nothing drops vitapods and I won't change my mind unless I get screenshotted proof.

@Zero-Chill
I have not seen it in YEARS, but it has happened before. Eventually they did patch it so mobs in LD don't drop anything anymore, so I doubt it'll happen nowadays.
Damage defense is not useless, but status resistance is more important (along with offensive bonuses). I have an armor guide that describes all of this. Maybe it will help you refine your opinion.
http://wiki.spiralknights.com/User:Jdavis/Armor
P.S. The idea that Chaos is objectively best is sorely tested by Black Kat.