As title says,
Since casinos are not giving any kind of free money and they have a house edge that guarantee the win for them in a long run no matter where do you bet or from which account, i.e. They aren’t either losers or winners. It’s usually used to prevent spamming by bots. The idea is that why would a bot dual account while they can change seeds and do everything from one account?!
I’M afraid there is a something we don’t know about this

If you ever visit scam accusations section, you should have seen atleast one problem from this kind.