But many people are not buying Bitcoin because of its usefulness, they are buying to speculate (hoping its price will increase).
One very important concept with BTC is freedom, now do you want to dictate to people how they should use a 'free' currency. I have never had a problem with how people use BTC, it is their keys, so it is their coins, and not yours or mine. I believe that instead of us complaining about how other people use their coins, we should use ours in the way we think is right and support the network how we can.