For knife making, sharpening, or...? Is this of any real use for an average knife owner?

"Power Hone Diamond Sharpener by Foley Belsaw" - $275 GB auction #339479909

It's being sold by a local pawn shop if anyone wants me to eyeball it.

If things were as obvious as they initially appear . . . then men would be riding horseback sidesaddle . . . and not women. - Will Rogers