Puting myself in the position of the casino, why the heck would I allow you to create two different accounts with same name doing same thing with the accounts perhaps it's must be for a suspicious reason that's why you would need double accounts hence it's included in all must all casinos TOS.
I believe this is one of the reasons why KYC was first introduced in the first place because it might have occurred to the casinos what some people might be miss using their bonuses and other things in their advantages hence it's very important for casino to include that as a term of service.
Bonuses and affiliate deductions are exactly the reason why players make an additional account. And account verification can stop multiple accounts from dishonest players, I have never made a second gaming account for myself because there is a risk of losing two at once and the risk will not justify the funds in this case.In addition, the site tracks the player's IP and often those who create a second account simply forget to change the IP, thereby giving themselves away.