TL;DR
When saving or loading games, it should display the date/time of existing saves.What ?
Because I game on several devices, I noticed that Steam save sync is a bit glitchy and sometimes it does not fully sync all of the saves. It would make it easier to identify the correct saves, if I have seen the date and time of the save.The diference between play time and save time is, that play time can tell us which is the longest played, but does not tell me, my saves did not fully sync and I am continuing a different save (with the same name).
I am sure there are many more use cases, like when testing a single game with several saves, etc.