There are no reasons. All the best games are on other platforms. Gamepass is a cheap ass non gamer crap for fake gamers who pretend this is their hobby. Psn+ is still better (I dont have any of those)
You are actively hurting your enjoyment if you are picking xbox over other competitors. Makes no sense. There is nothing there that's not on other consoles... but it runs worse, plays worse (no dualsense stuff) and lacks the some of the best pc or ps5 games that are not there.
If you are exclusively xbox gamer, you waited for years to play f16 and 7 remake. Waited for years to play wukong, Waited longer to play BG3,
Continue to wait for ff7 rebirth which might never come. Same with Rise of Ronin
Waited years for Death Stranding, Some ps5/4 exclusives... If you are exclusively xbox gamer you never played last guardian, bloodborne, Demons souls, returnal.
Even Nier automata came out year later. Stellar Blade? good luck. Astro, ratchet, forspoken (f you, great game), horizon, infamous.... etc etc etc.
if you are exclusively xbox game, you are hurting only your experience and not proving anyone, anything.
But hey, gamepass ! you can play indie games and rare normal game for 15$