First, you likely don't need bottom paint on your boat unless you will leave it in the water for an extended time. My boat came with bottom paint and, like you, I'd prefer if it wasn't there. I also don't care enough to actually remove it.

There are a couple common types of bottom paint. One type is a "hard" epoxy-like paint. It offers less drag than the alternative which is "ablative" paint. Ablative paint is what I have and I believe it is considered more effective at preventing underwater growth because it contains a bunch of copper AND it "sheds", meaning that it will wipe off on your hand if you rub it, which sucks.

You CAN remove either type of paint with the right effort. Some allow you to repaint portions that wear or chip off without having to redo the whole bottom. Also, you can SOMETIMES put a different product over the old paint but you will want to check manufactures' suggestions.