Yes agreed, AUV's prefer a flatish surface underneath them Gregory to make best use of the technology. It became apparent early on that a reef face like the Gardner seamount was going to be a challenge for sonar, too many grooves, caverns, holes, ridges, plates, boulders, shelves, gullies,. Too many false targets hiding real targets...?
Still, the ROV won't be so easily misled, it records what is there and, makes it easier to sort out the above from...?
They were able to identify and eliminate NC wreckage quite easily but aircraft wreckage won't survive as well as ship wreckage in those conditions.
All IMHO of course