And that's a good thing, people who base their characters off of tiers are tournyfag douchebags. Even in competitive play, using only Top Tier characters is retarded, I agree. Basing your mains off of tiers in friendly play is even worse, it's why I play Wolf; he's middle.
However, in the highest of tournies, you NEED to play Top Tier, it's literally mandatory. Unless you're a ton better than your opponent, and I mean by a long shot (which is nearly impossible in final matches in tournies such as nationals or worldwide), then you'll definatly lose. ... Besides, when money is on the line, you want to win, yeah? :P
That, and tiers were never meant to tell everyone to main this character, or not main that character. It's simply a rating chart based on the character's current metagame, as well as how they in general match up against other popular contenders. If you're thinking I pay attention to tiers only to tell people who to play, you're sorely mistaken. :P