This is the way that a gambling fund needs to be treated, even the professional gamblers that earn money out of the activity have completely different allocations of money, the money they use for gambling is not used for anything else and the money they use for groceries and to pay for everyday things is never used to gamble, this hard separation of those two capitals is what allows them to gamble with confidence as they know that no matter what happens they are not putting themselves at risk of losing all of their money, and this is a policy we should follow.
It is correct that it is the professionalism of the player that allows him, as a person, to overcome his passion and stop without touching money for everyday needs. However, for this you still need to have a completely pragmatic mindset and be smart enough and not too reckless. It is the combination of such qualities, in my opinion, that is the main property of those who are considered professional players.