I think i get the general sentiment but this bit here:

but the reality is in genshin impact nothing else matters.

We are talking about a game where you go from killing something to killing something else in the time it takes for your hard drive to load their models. You have to be prepared to deny any damage taken at any time, whether before you take it or after, shields and heals are the only way to do that. Yes, shields and heals are important, never more so than the current patches. If you're dodging every attack you're spending less time doing damage. If you're taking damage and swapping to a healer, you're not doing as much damage. If you don't have a shielder, you're getting interrupted, which means you're doing less damage.

the higher heals you have, the less impactful a single hit can be. Heals = damage. Sure, overhealing doesn't do much if you could be doing more damage without it, but that's not the case with bennett. This person is saying they like their bennett to have higher hp, and generally want the best weapon to do that with, because of the limited options in terms of hp swords its understandable to want something obscene like an archon's weapon just for your bennett if you use them enough.

Me personally I'd like jussssst enough healing / offensive capability to make sense and not more. If i focus on healing rather than playing smart, I usually find myself fucking up my rotations and doing a lot less damage. But - if say, the hydro archon buffs your team by dealing self damage to your on fielder, you'd better hope you have enough healing to compensate.