Personally I could care less about them. The only thing I like about them is the same thing you like about 'em. When people are bragging about game accomplishments, you know if they're telling the truth or not. (If the game has trophies of course) 
What's sad is that people get so caught up in achievements and trophies, they're willing to pass up good games that don't have them. I've had a few people tell me that they didn't purchase Valkyria Chronicles because it didn't have trophies. Now, it takes a bit to aggravate me, and that definitely aggaravated me. They're virtual icons. Jeesh. Just my humble opinion.
Person 1: Does Valkyria Chronicles have trophies?
Person 2: No.
Person 1: Forget it. I'm not buying it.
Person 2: Wait! It's amazing! Unique, charming, drop dead gorgeous... Hello?
