I believe xibeijan's concern is that if you were to sell the Alias, and give the buyer your Nxt account password, you (seller) would still have access to the account since you know the password of the Nxt account.
I know. I already explained this situation a few posts ago.
Yep, he didn't see that, I'm wondering if it's better if we open new Nxt account per Alias or just have all Alias associated with main Nxt account.