No, it's a sandbox game, there is no "right" way to play.
I play on peaceful when:
1)I'm Building something large.
2)I'm in my testing lab world which I use inventory editors and various mods.
3)I'm in dire need of resources for a large project i'm going to be working on so I spelunk on peaceful so I can be significantly more time efficient.
I generally play on hard the rest of the time.
I don't think it is noobish to play on peaceful some of the time, I find there are good reasons to do it.
I do think it is noobish to ONLY play on peaceful because I feel like you are missing out on a part of the game. I think everyone should try to play on at least easy every once and a while.