I tested it a little.
Yes, indeed it make it easier to tag while playing.
But still the concept is a little different.
Currently, in the enumerated tag way, the tag list is based on what is exist on other tracks. Whenever removed from other tracks then is removed from list. You can't clear all the Custom1 tag from all tracks, and start over to tag by the list you had before.
BTW, it is not so intuinteive to configure, and I think it's not work 100% well:
1. The "Configure Fields" button is is placed far away from the "vertical tag editor"
2. Rating type didn't work well for me. It's not editable.
3. There was annoying "Confirmation" dialog-box each time you edit. You can't edit freely, song by song, with just one (or two..) click.
4. i think the list database is not live updated. I needed to Exit and Run MusicBee again to find the new tags I'm editing, really added to the list.
As described before, I'm talking about a new tagging mode, where the tags list database doesn't depend on the tags of the current library's tracks. It is independent, and managed by the user.
I think it's important to make a distinction between
Information tags, which basically give details about the song. Those are the normal tags, and supposed to be fixed.
Customizable tags, which are things that can be changed by the user's mood.
I also think that the Information tags need to be saved to the files themselves, and the Customizable tags need to be saved to an external database, among application settings files.
I would happy to see such tagging mode in MusicBee in future.