Well, this was a surprise. I thought for a player who has been with Real Madrid throughout his whole season well probably wants to stay at Real Madrid for another season. But it seems like he is actually choosing money. Which is absolutely fine, especially at this stage of his career. he is quite old and it is best for him to actually grab the money that he can get right now.
Once the age of a player get closer to 35, he should take cautions about his future with Real Madrid since the club will offer always one year contract, at maximum two years contract with no guarantee to play full time and might even find himself in the benches the whole time depending from his performance but essentially from other players performance. So it is normal for any player to go find a suitable team in a suitable league for his actual performance to look more important than being a normal player in Real Madrid. Besides money won from Saudi Pro League is always higher than any other league.