Seems I'm the first dealer to reply here.
I get paid pretty well for dealing. But I work for an events company that does corporate functions and private tournaments, not a casino, and they look after us really well. I work with a lot of ex-casino staff though and they're almost all glad not to be working in casinos any more.
Either way (casino or private) though, the hours can be pretty lousy.
Then there's the drunks and douchebags you have to deal with. I just came in from a really crappy shift, so maybe I'm bitter on that point at the moment. But you really have to have patience. There's a fair bit of pressure working in a casino too. You have to track pots and calculate rake, plus learn the mechanics of shuffling, pitching and chip handling (the last two particularly aren't as easy as they look).
As to whether it makes you a better player... meh, I don't think so. Maybe you get some practice reading people, but most of the time you'll be too busy actually running the game to watch closely. For my money, I think you'd get a lot more value from actually playing say four hours a day (either live or online) than you would from dealing eight hours a day. If I weren't a dealer, but I'd still done the same amount of reading and playing, I think my game would be pretty much the same.
Anywho, Cliff notes:
Become a dealer because it's something you really WANT to do - not because you think it'll make you a better poker player or because you've got nothing better to do. Because it won't really improve your game that much, and the negatives will fast outweigh the positives if you don't actually enjoy the job.