I think the two main reason for resetting deep gravel are
1) A deep bed cultivated from gravel is aesthetically displeasing if one doesn't know what it is. It could be the most biologically amazing substrate bed around, but anyone who doesn't know what they're looking at will just wonder what the heck happened down there.
2) It takes a long time (4-6mo) to cultivate a deep bed when you start with a tightly graded sand. Starting with gravel, probably twice that, and the road there will be (a) aesthetically terrifying, and (b) arduous if one isn't rigged for easy pwcs and possessing a veteran approach to feeding.
I suppose I leaned heavy on the deep bed bias. Apologies. It *can* be done and I've done it - but I wouldn't do it with gravel again so I probably shouldn't bring it up in a thread about gravel vacuuming. Especially since my first recommendation for a deep bed would be "replace the gravel with #20 sand".