I rarely found much worth buying in EITHER game. Most my money went to SDUs in BL1...
I've seen the occasional really good shield, or nice rocket launcher in the shops, but it's mostly fodder. Although, upon starting PT2, I was spending a fortune at the shops to fast track my survivability; Because, once you start PT2, you quickly realize all your gear sucks.
Not useless at all. I normally check them whenever there's one nearby, and every now and then, they offer a good item or two. Maybe not at lvl 50, but at least while leveling. That's all I need really.
I do not suffer from insanity. I enjoy every second of it.