EDITED: To late to withdraw so I am just deleting my original text!!
When I want to show the filed value, but do not want user to manually edit the value through the form or quick edit, I usually set the editif constrain to false. This still enable actions, workflow to change the value I remember.
Based on your comment, I created a tester app to play more and I guess I was wrong in my original statement. I have recently seen issues where the automation cannot update and played around in the context of that app but now I am not certain of what was going on.
I am retracting my original statement!!!
Im with you, yes, i recently thought the same stuffs, as editif expression seemed not working as I expected. As i refreshed my mind after testing like you did, I solved my own issues.
The issue I was referring to was an error that stated the column was not editable in a workflow rule action. I was forced to implement a CONTEXT() function to bypass the error as I wanted the Workflow full control to change the value. I don’t believe I should have needed to do that.
I cannot seem to replicate it with a little tester app so I’ll have to play around more to isolate the issue and reassess.