Tell me one reason to give Pyke the sustain he has?

Notwithstanding his winrate as a support, please tell me why an assassin support with better CC than most supports and damage and mobility on par with assassins has the best sustain passive in game ( I believe).

No i have not been facerolled with a Pyke recently and i do get to face this guy often and i manage to hold my grounds by choosing Brand and etc. However, the issue is that no matter what i do in lane, I JUST NEVER POKE THIS FKR. You'll waste more mana by poking him than his health. I believe someone like Pyke who has enough CC and damage to kill you if he engages correctly should not have that much sustain. I have no idea why are all the new champs made so cancerous.

:<