A few interesting comments from DF relating the PS5 Pro on their latest 'weekly' podcast. Quite comical that Sony are renaming 'boost' to 'Ultra Boost' mode, it feels like they've taken lessons from the school of Apple or Intel with their naming conventions (iPhone Pro MAX, Intel Core ULTRA).
It definitely sounds like games that currently are a bit wobbly in their performance modes should get that entirely ironed out by just existing on the PS5 Pro (so games where it's variable between 55-60 will benefit) - but also games that have an unlocked FPS mode (Horizon Forbidden West Performance) will likely really benefit here too. For those that play MW3/WZ3, the performance mode on that game runs up to 120fps but typically sits between 95-105 so the extra performance should definitely provide more consistency there as well.
I think what interested me the most is that apparently PSSR can be injected into any existing PS5 games - and then it'll be a bit of work for developers to have it working as they'd want. They note Jedi Survivor being a good use case for this where it's quite aggressive with it's use of FSR so I'm really hoping a few of those games are revisited. FSR is alright, it's not great and it's comfortably behind Nvidia's DLSS (and probably behind Intel's XESS right now) so hopefully PSSR can help games consistently run at 4k60 whilst still looking as great as they do with DLSS.