However, for us or for those who gamble to the same website would not be able to know who he is.
Who knows, he might be one of the member here in the forum. We do have a lot of crazy rich people around here. That's the reason why gambling websites and other crypto related projects loves to advertise here.
That is possible as KYC are now being asked mandatorily at those big winnings. These whales are also probably now on the highest VIP level and their perks are really awesome that even they are losing, there's something special in return provided by the gambling site.
But sometimes there are rumors that those winnings are just show off to show that there are whales actively playing on the site.
I just can't think of a reason why should it has to happen just to attract users on the said site.