Getting on would be tricky, I rekon you would hit the board with you harness hook quite abit in the process.
If you got yanked over the front or hit some shop hard you wouldn't have as much body movement to save yourself face planting.
Chop would smash you round in general.
your body would be at a 90 twist the entire time which could be painful (thought buggiers do it)
and yes, Peter Lynn was making a sit down (kite boat/ski) thing back in the day of kitebar reels and ARX 5's
positive input...riding waves would be smooooooth as