The thing PC crossplay will indeed affect is that pulling Strategems using keyboard keys > controller. Much more precise, and less error prone. Folks will still choke regardless of what type of input device they chose but yeah, for the 12-15 maps, joining a PC player may not be a bad thing. Unless, well, they start doing griefer shit like teleporting around the map or one-shot killing everything, thus breaking the game.
@On Demand does make a solid point about crossplay. If crossplay is enabled by default in the PS5 version, those that turn it off will be disadvantaged by being under a smaller pool of players. I think from a developer standpoint, a way to combat that is to have crossplay disabled by default - thus most casuals won't know. That is to say, making users who want to use the option to manually opt into crossplay in the menu's as opposed to being the default option.