These posts are so ridiculous - we get it, you're happy to share a bathroom, good for you!! Not everyone is or wants to.
I think it sounds a good idea. It's ok sharing a toilet if people you share with are clean but I totally get what you mean about pee on the seat etc, when I see this in public toilets it turns my stomach. You don't know how clean the other people you share with are going to be.
I probably wouldn't poo in it though because it might smell if you're leaving it in your room for a while (I dunno how often you would empty something like that) I wish I'd thought of this at uni.