100% of the time i'm laying on the floor next to a bike. So much of my experience is from that initially uncomfortable position that now anything raised on a bench just feels awkward. Like all last night I was rolling around on the floor fixing a tomos that I had leaned up against the bike lift. the lift just winds up being a stand to lean shit against, it's just weird and annoying to have the bike lifted up
but to your question - I could answer why I feel that way.
1) it sucks trying to start a bike up on a bench. I can pedal a bike on the ground.
2) it sucks getting to the controls on a bench, you're reaching over your head trying to twist the throttle, on the floor it's comfortable reach
3) shit gets lost on around or under it. same with the floor but there's less room to lose stuff
4) moving it, moving around it. it's so much easier just stepping over a bike than going around a bench, sliding a roller seat around a bike on the floor. turn it how you need it, lay it on it's side, whatever, bench has 1 position
plus there's no setup on the floor, you don't need to roll it on, lift it up, chock it in place and strap it down (or up) - you just lean it or toss it on the stand and get in there.
5) aligning lighting. there's no directional orientation on the floor.
so basically if you could make the bench into just being the floor, that'd be cool