It will be easier to manage our gambling funds if we play in 1 casino only and the rewards we may maximize the possible VIP rewards from the casino.
Of course it is also based on my personal experience and you have your own experience as well as your own preferences about this thing.
At the end, our casinos may become useless once we stop wagering for long time because VIP program will always based on our gambling activity.
So having 3 mature accounts, I guess will not make this user deposit any further after all the benefits can still make him play around all those 3 accounts. No wonder there are VIP casino accounts that are for sale.
I really admire the way some players can have more than 3 accounts and all in VIP style, they must have a lot of money in there or have played it , in my experience I have little time with my account, where I have it more mature is in Duelbtis and I do not feel that I can reach the level of a VIP, because my bets are very low, I do not make large bets, I only make bets that my income can afford , I also like the casino because it entertains me , I am not looking for profit fast or become a Millionaire , just have an account where I can Enjoy and where they give me Loyalty benefits.