Like everything in Belgium nothing is black and white, there is always room for interpretation. The gaming commission is about the protection of the player. Poker is a product in which beside lottery and scratch cards there is least chance on problematic addiction(Van Rooij, 2017).
Lottery: 6,8%
Scratching cards: 7,1%
Poker: 12,2%
Sport: 17,7%
Casinogames: 22,7%
Gambling automates: 26,2%
This study is used by the gaming commission itself.
Offering a form of cashbackin casino games and not in poker just doesn't make sense. There also isn't any article that RB is prohibited in Belgium, and in fact GG is offering personal RB deals up to 65%, and Stars is also offering some form of RB; for about 3 years allready!!! Without any warnings.