Especially all newer casinos like Wolf.Bet, Windice and co do this. There are new events (sometimes even on a daily basis), new games and leveling systems to keep the players happy.
Sites like Bustadice, which are more focused on "mass games" (hence the native script support), don't need that and usually don't offer such features.

@efialtis ... and now I have an idea (yes, it happens from time to time ). You already have all the comparative data of the casinos. You could provide a "you may also like ..."-feature, which recognizes for example, if a player likes to play Casino A, he should take a closer look at Casino B.