I don't think this applies to everyone, but I have personally tried it and the results were beyond expectations, I also have accounts on many gambling sites and when my luck is not good (when playing slots or dice) then I will try to play on other gambling sites and the results are satisfactory, a few weeks ago I also did that again and when playing on coinplay, I got good results.
The casino has the same rules of diversification as in investing. You can't get hung up on one casino, because over time you can start losing money in it, you need to play in different casinos so that you have a choice and you know the features of each casino.
Maybe being active in several casinos will benefit as mentioned by the members above but there are also drawbacks, usually players playing at casinos also have targets, for example to reach a certain account level so they can benefit from high account levels, so focus on one casino or play in many Casino has advantages and disadvantages