As someone who vehemently prefers scope ratios over flat, I have to come out and admit I feel Beauty and the Beast is an exception. I saw it in both ratios, and it felt like it was really composed for 1.78:1 and simply protected for 2.39:1. It didn't seem like there was extraneous vertical space when seeing it in IMAX, not even during closeups.
Obviously, the ideal would be to include both as it was presented both ways. I find it strange that even the foreign 3D releases are in scope (as far as we know) whereas Disney usually presents its 3D Marvel films in a flat ratio on BD.