i do it for 2 reasons:
1. It is awesome... Who doesn't want to squat an extra 100+ lb...
2. It is harder. The best raw lifter is not neccesarily the best equipped lifter. It adds a whole new level of skill to it. People say you can learn in a couple months, which you can. But to wear tight gear and get the most out of it, you need to be willing to work hard, train smart, and develop some major skill/have some major talent.
As far as different gear:
Knee wraps are the most basic, not really gear, but they should add a lot to your squat for sure. Often people get more from wraps than a single ply suit. Knee wraps are my favourite piece of supportive equipment for sure.
Squat suit... Takes soem time, but with decent coaching not too bad. Once it is tight though it becomes hell I think. Mostly just learning to do exactly the oppposite of what the suit tells you to do.
Bench shirt... I almost lit a super katana on fire once. Not straight forward. I have insane respect for multiply lifters. How you can wear something like a double ply super katana and get it to your chest without your eyes coming out of their sockets I have no idea, but good on you. Perhaps a bit excessive in some cases (getting like 350lb from a shirt) but hey, people who can figure it out are 1/1000000 and deserve their credit.
Deadlift suit... For me, was really simple to learn but I could see how something tighter is hard to learn and probably harder for conventional pullers. I still get a reasonable carryover from my suit.
IMO, as long as you compare yourself to people who do the same thing as you, every level of gear is unique and has it's merits. Don't bitch about one or the other.