This is an extremely important feature both for convenience and safety.
Like, people have their mods break all the time due to updates. And auto-updates don't help at all. I myself have had issues where steam sometimes automatically thought that my modded game needs fixing (which is linked to auto-update) and I could never disable it.
As for safety, the game People Playground is a great example. There was a recent malware attack where the malware injected itself into most of the mods on workshop. The main issue here is that steam auto-updates workshop mods as well so this can lead to users getting unintentionally hit by a malware (although I don't think it would be serious, but still an issue).
Steam does a lot of great things for consumers, but I think this is a must have and should be implemented ASAP.
No matter how much shit we give to EGS. Even EGS has this now.