Full disclaimer, I have a Series X and a PS5. I throughly enjoy both systems, Sony IME is very slow to roll out features.
Having started with a PS5 (as my first current gen system)and going through the slog of re-downloading every PS4 game that had an upgraded PS5 version and going through the inconsistent (sometimes non-existent) transfer of save files; smart delivery was a breath of fresh air, a patch on the game that had been transferred over from my old Xbox and I was ready to play the next-gen upgraded version of the game (save files were seamless).
Regarding your statement "Xbox isn't first at anything"; facts would dictate otherwise:
Xbox One X (2017):
- Object based audio (PS5 2020)
- ALLM (PS5 2022)
- VRR (PS5 2022)
- 120Hz (PS5 2020)
- Dolby Vision HDR (not planned/never)
Xbox Series X/S (2020):
- Ability to add additional storage for next-gen games (PS5 2021[M.2 support])
- Smart delivery of next-gen games (never?)