Public servers > Crappy home-hosted servers
^this is a fact.
You're approaching this too simply, Jay. Take america's army as an example. It's free, and there are both public and private servers, but people only really play on the public ones as they are :
1. Quicker
2. Managed by official admins, so there is less flaming/spam/etc.
Also, as Nuthug pointed out, you couldnt earn Qi/credits on a private server. Whether you like it or not, Qi is Nabi's way of classing people by experience, and if someone was a bluebelt with 86,000 games, who could enter beginner servers etc, then that would be detrimental to the game, no ?
Anyway, it is the way it is, and it isnt going to change, and you *will* most likely get flamed for multi logins on the same account. But, atm there is no rule that stops you from doing so. If/When there is, you can either stop, or leave.