why dont kite foilers use sit-on type airchairs?

why dont kite foilers use sit-on type airchairs or skyseats? i have only seen kite foilers use foilboards and would like to know if it is possible to use the sit-on type? and if not, why?
thanks

when you are used to stand up like kitesurfers, you simply are not thinking about sitting.
My 2 cents

thanks for the reply
the reason i am interested in kite surfing with an airchair type set up is that i want to use it for coastal cruising. i would modify an airchair by creating a watertight compartment under the seat to store basic camping equipment and food. this is my basic idea so i was just trying to find out from people who, unlike myself presently, do kite foil if they think this is possible? and/or what would be needed to be overcome to make it possible?

Hey, Coastal riding is THE excellent idea ! Foil can go upwind as good as downwind so they are much better suited for long rides. You don't need to find the downwind places.

I thought about the same practice than you are intended to do. But thought about other solutions.

Either a 100% waterproof backpack with say no more than 5 to 6 kg. UL material is now available on the market for hikers that would do it properly for this project.

or some material harnessed onto my board. Be aware that I use a 170 cm long board... You could use a Malibu board too, it works good.

I even thought about some light inflatable surrounding that would transform my board into a inflatable stable boat I could sit on to reel in my lines in case of dropping wind.

Sailing, if you have the time, is the superior way to travel IMHO. The thing holding people back is its unaffordability. Kites may not only make it possible to have a craft that is affordable but also may make it possible to have a craft that is FAST !

Laurent, 5-6 kg doesnt sound like too much to carry. When hiking i have used small pouches that attach to the front straps off backpack harnesses that might distribute the weight better - helping your endurance. They call them balance pockets. Remember UL hikers are going far from civilization for days at a time, most of the coastlines of the world are densely populated so you could be resupplying constantly-cutting the weight further.
From a safety point of view a surfboard is a very seaworthy craft but I was wondering how does hving a hydrofoil attached effect its ability to be paddled ?

My own ideas for a design are;

-airchair + kite

-ski biscuit + kite

-surfski(with removable keel) + kite

the ski biscuit design would be for downwind travel only and the tow line to water surface angle would have to be small 20-30 degrees. This design has the most unknowns for me so if any one could conceptualize it for me, it would be a great help.