If you wan't to buy any coin, and i mean any coin, which coin are going to trade for it? Well what about the percentage of people who are going to do the same thing? I'm not going to risk any number but i would bet it would be quite high.

You can make a possible valid point that it shouldn't be that way, but it is. And that's a huge use case. So saying bitcoin is useless seems like a bit of a stretch.