is an MBA that useful?

hey guys I was wondering about why people rush to get into banking regardless of the division work for a couple of year then go and get an mba, IMO its useless because why get an mba for a position that u would have gotten anyway if you stayed at your firm (analyst to associate) and the exit opps (specially for IB people) will come from your experience in IB for example if u wana move to PE or hedge funds having work experience in IB is more valuable than an mba. I can only see it having two benefits if someone wants to transition from one industry to another (have to go to a top BS), or if he comes a very technical background and wants some business expertise. any thoughts ?