I only meant for avoiding getting warned, not building a godlike ratio/amount of points in order to reach the top-ten, but thank you for answering anyway :]
They are not ratio builders. They can help those with horrible connections, but definitely not something you should rely on for ratio building.
Their purpose is to keep torrents alive and reward those who do.
I guess you're right, it works for keeping obscure torrents alive as people who have a good connection and great ratio also want their points because of prestige.
I am not fully convinced on the "help people with horrible connections"-part, but you've probably heard that a thousand times, so I'll keep quiet.