I think it is a matter of getting used to.
Foil kites are way faster to launch, than any LEI kite, because you dont need to inflate, and you can roll and sort the lines out extremely fast.
With my Peak4, I timed it once on a summerday, just to see HOW fast I could be ready (at a spot where I could launch and land just at the side of the car).
2:00 minutes from I parked the car, till ready to go on the water, meaning 120 seconds it took me to:
Foil out of the car, assembled (if not, I only got one screw so does not take long).
Harness out of the car and on (summer, so only shorts, would take 20 seconds more if having to get in a shorty).
Kite out of the bag, lock the car and hide the key.
Put the kite on the ground and roll the lines out and launch, trusting lines are sorted as they usually are on these kites.
It would take A LOT longer to inflate a LEI, and roll/sort/connect the bar (as most do with LEIs, myself included)
Even with lines attached, a LEI takes a lot longer, you also have to close the valve, takes time too.
Packing down, I had to use 3 minutes before I could drive away:
Backing the kite down.
Get the key, and put harness in the car.
Rolling lines up.
Put it in the bag.
Foilboard in the car.
And it would be closer to 3½ minutes, if I were to get in dry clothing, meaning shorts and maybe T shirt.
Still, I timed how long it took with LEI's some years ago, it took a lot longer !
The most time consuming part is if you have a full wetsuit, especially the warmer ones, it takes much longer than rigging and launching a kite, I found out.
I dont rush like above normally, but because I had been out in one spot, wind died, I drove to another, wind okay - I had the chance to time HOW FAST I could be, from parking the car till standing ready to go in the water, kite in the air, board under my arm
It was fun, and amazingly fast, I had an idea, but did not knew exactly !
With big lightwind foil kites, setting up is very fast too, a bit longer though.
But packing double skin foil kites DOWN, is horrible - it takes so much longer to get these deflated and packed in the bag, that everything you gain on the start compared to LEI's in terms of less time, is more than lost.
It does not matter much though, as the important part is usually a quick setup, so you can get on the water while there is wind and light.
Packdown can be done after sunset, and/or where you are relaxed hopefully after a good session