An XDA contributor claims to have found an option to switch a screen's refresh rate from 60 to 120 hertz (Hz) in MIUI 11. This suggests that there is an upcoming Xiaomi phone with this spec in development. This would leap-frog the new industry standard of 90Hz nicely.
https://www.notebookcheck.net/Xiaomi-could-be-the-next-OEM-to-the-120Hz-display-new-rumor.438725.0.html
I don't think we have enough battery to be pushing this tiny bit of improvement in UI experience universally. On a gaming phone it arguably makes more sense.