Creating multiple accounts is of course a common practice, including in Gambling. And it is obvious that in many cases this violates the rules of using the casino. And I think that of course it would be right not to engage in such creation of multiple accounts, and even more so entire farms with different email addresses, for example, controlled by one person.
You're right, creating of multiple accounts is a common practice for some people and they try their best to use each and every available technique to hide from the platforms that they have multiple accounts. Even at Bitcointalk, some spammers have multiple accounts and they spend countless hours to promote spam from those accounts from time to time.
It's a corrupt type of practice to have so many accounts on a platform and only those who are corrupt people indulge in such type of multi account creation in order to abuse a platform. Account farmers used to create so many accounts on Bitcointalk back in the day when merit system wasn't introduced and similar type of accounts farmers or bonus harvesters make multiple accounts on casinos to avail bonuses multiple times. When a casino finds those people then they either came with many excuses or admit their wrongdoing.
However, now that there are already opportunities to use AI to calculate and block multiple accounts of this one person, this practice will apparently (I think) gradually begin to come to a normal phase of development. And the practice of creating multiple accounts and farms by one person will gradually become very difficult or even simply impossible. So let's assume that this practice was temporary and it will end pretty soon.
By the way, this means a complete de-anonymization. Apparently, this is inevitable. Although this also has obvious disadvantages for some aspects of a person's private life and secrets.