Backwards compatiblity, quick resume, solid online services, and (for a while) great hardware prices (Series X in particular, but Series S too during discounts).

Yeah on that point I'd say them being quite forward thinking is one of their strengths overall; first to make HDD standard, normalizing standardized off the shelf architecture, pushing online hard before Sony or Nintendo really bothered to, focusing on indies before the others did, etc.

Things I like about my Xbox Series X over my PlayStation 5:
The console runs super quiet in comparison to my PS5 Pro.
You can get Microsoft points while gaming that you can use for £5 store gift card. The achievements, the way I can see my friends online on PC. The 360 days were great with the "arcade" games (indie games). The Rog Ally S/X is brilliant!

The backwards compatibility is brilliant, last night I was having a blast on Joyride Turbo from the 360!
The Series S is an awesome little machine as well. Very underated! Controller options are great, you can use a old Xbox One controller or a modern one. You can use a Elite Series 1 or 2 for example. PlayStation locks you out with the older controllers.

They still have almost as many games racks allocated to xbox games as playstation games despite the low sales, so i guess they have marketing, or rather perhaps the games are boyied somewhat by the power of the various Windows based products. But this won't work forever, and we see XBOX slowly dying anyway.