In the case of marketing strategy, any site are free to claim themselves as bla bla bla but players are those who decide whether the claim is true or not.
There are many casinos out there that claims themselves as "the best", "number one", etc so I can say that it is a normal practice by casinos to attract players.
What you need to do is to find it yourself which casino suits your needs/preferences.
If you are looking for rewards offered by casino, you can simply compare it yourself by visiting them one by one.
If you are fish selling on the street, you are always yelling that you are selling fresh fish.
The same in the casinos, everything they can call themselves the best of all the best as long as people will lure to them gamble, their experience will speak and have to decide whether they will stay or leave and it will depend on their experience.
So rewards and high RTP will definitely catch gamblers' interest.