Yeah, it kind of is an oxymoron. Although HDR and WCG are generally lumped into the HDR moniker when they really should be stated as separate entities.
The B&W version in HDR is actually kind of nice. B&W films are not generally my thing, and I didn't particularly enjoy the B&W version of Mad Max Fury Road. Logan, though, I've only watched about half of the movie in B&W. I actually am enjoying it; definitely a different feel to the movie. I'm so glad they decided to bundle it in with the regular release instead of putting it out as a separate version you have to fork over more money for.