Who Does It Benefit
Marketers and Developers (because helping marketers is the developer's job 🙂)
Value To Be Gained
The developer would be able to more easily make a marketer aware of the existence of a field/setting, and convey reason as to why the field is disabled.
I think it would be nice if we had the ability to disable module fields based on certain conditions, similarly to how we can hide them completely with display conditions. Unlike hiding the field with display conditions, if they were only disabled but still visible, developers could provide help text regarding why the field is disabled, indicating what the marketer can do to unlock the field. This ability to disable would be nice for global theme settings as well.
I think it would often-times be more confusing to hide a field completely based on another setting, for a marketer. Sometimes it makes sense to hide a field completely, other times I would imagine a marketer would be confused or disappointed as to why a setting is missing --- in those times, it seems like it would make more sense to disable the field so the user knows of its existence, and the developer can provide help text on what the marketer can do to unlock that setting. That isn’t to say I think disabling is always the better choice, I just think there are some times where it would make more sense to disable a setting (so the user can still see its existence), and other times to hide it completely. Otherwise, the user may simply think the option doesn’t exist in the module, where it may exist, but it’s simply being hidden by another setting.