If you don't have a problem with extra disk space, backing up the whole folder is easier and safer, especially if you have mods. For me, I daily backups for saving files and still keep the files of each day in case I want to go back longer than the recent one.
Some corruption was hidden in the game for a long time before taking effect such as For Rent bug. So you should keep the daily or weekly backup save because you may have to flashback more than you thought. (But I hope it doesn't happen in our games.)
I never use memory systems either. Because I save over 100+ screenshots each day, it's impossible to save in The Sims 4 folder forever. And for in-game photos, I usually delete unnecessary photos to keep save files small too. Big save file is one of the risks of corruption. So, we have to avoid that.