I don't think it's good. I'm a strong believer of people developing as individuals, and individualism being valued more than conformity.
It's not just about "falling in with the bad crowd" it's about placing the need to impress others above your own beliefs or values, and developing your own personality. Succumbing to peer pressure does nothing but encourage becoming yet another drone who will do anything to fit in. One shouldn't decide to shower just because everyone else is, they should do it because they respect themselves and the learn about the benefits of good hygiene.
Drugs, smoking, drinking, I did all that because I wanted to. Nobody told me too, in fact most of my friends at the time looked down on me because of it. The good route, the bad route, the neutral route, the apathetic route, the bad hygiene/good hygiene, whatever, anyone can end up taking any path regardless of whether those around them are taking the same path.
Yes it can have some positive acute effects, but the deeper impact of learning to just go with the crowd should always be avoided imo. If you just do whatever everyone else does, the negative impacts will outweigh the positive; "most people" are not model citizens. It's okay to change the way you act in front of others for social acceptance, or even to just avoid hassle, that's natural and everyone does it; but having a real need to change your whole personality, actions or way of life only to fit in is just not healthy.
I know if I gave in to peer pressure I'd be 10x more of a **** than what I am now, god forbid.