Casinos are a business like any other and want to make money, so if a user is losing money and giving profit to the casino, they will want to keep hin in house as much as possible.

So yeah it makes sense to give this user more bonuses and rakebacks, because at the end he might still lose more and the profit keeps coming.

But would you call this type of gambler vulnerable? Maybe he has fun gambling even if he loses money when the day ends.