If you want to treat it as a hobby, you can. It's pretty much up to you how much you want to get into it. There's always going to be some sort of learning curve, but depending on what you choose to use, it can be small or large. There are quite a few noob-friendly distros out there that (for day-to-day) should only have you learning where the Internet icon is and that there's no "Start" menu, per se
What do you get out of it? Depends on how much you put into it (cheesy, I know). The more you dig, the more experience you'll get. It's hard for me to say "you'll learn this, this, and this". You'll learn a lot just by installing, but that's general "this is how linux works"-type stuff.