By design, I keep a lot of large files on my USB drive, but this also has most of my user data, so I can use a computer in the UK and one in Spain equally well. This is a good candidate for the 'Move' option.
But my internal drive isn't a good candidate for it.
It's easy to forget to change this option depending on which drive I'm defragging, and the time penalty for such forgetfulness is huge.
It would be nice if this were settable drive by drive, as my drive letters don't change very often