Actually, I'd argue the user's conceptual model is different. From the user point of view, they are telling MB to create a release, which has track artist credits, and to create corresponding recordings. Of course the track artist credits are copied to the newly-created recordings as part of this operation. So, according the user, this box should be checked.
It may be that the MusicBrainz code sees this operation as several "edits", and that one "edit" which creates the Release doesn't yet have any Recordings to copy to, while the Recordings are created as part of a different "edit". The user won't be aware of this. It looks like a single operation to them.
I don't propose a change to the behaviour of the code, I just propose a change to how the MusicBrainz web UI communicates with the user through this (checked, disabled) checkbox.