See here: Alteration Request: Make MP3Tag Not Touch Files Unless It Has To
Is it? You've never had a slip of the mouse?? That is a lazy assumption by the software and not user-friendly.
Just because it doesn't, doesn't mean it couldn't. Write comparison need not be required, just a flag to register input has occurred and not just that the tag field was highlighted. I would also suggest nothing should be committed unless Enter/Return gets pressed (which is the data-processing meaning of that key!). People who do want changes committed regardless could have an option setting.
Change the user to suit the software rather than the software to suit the user? Hmm.