While I do promote seat belts, I think they can be flawed too. There have been many people that the seat belt comes unlatched on, when impact occurs. There was a story about it a number of years ago.
In general though, belts are a good thing to invest in while getting in your car. A friend of mine was drunk driving about 3yrs ago, and hit hit a Ford Explorer with his Lexus. The Explorer rolled, and everyone but the 15yr old was wearing seat belts. The 15yr was ejected, the Explorer rolled over him, and two days later they pulled the life support on him and he passed on.
Yeah, I knwo what you mean..they have their flaws and aren't perfect, but honestly in any colision over 20mph they will save your life... everyone plays them off and drives without them, until they see that police video in high school where the dummy gets ejected like a godamn missile in a head on colision @ 80mph... I remember seeing that in high school and going 'holy shit...that looked like a f*cking rocket!!' ever since then I've always worn seatbelts and like I said earlier, some dumb ass 17 year old that just got his licensed plowed right into me at 80km/h at an intersection, if it hadn't been for my seatbelt I would have been a dark red splotch on the wall about 60 feet ahead.