In foil jibes i feel that speed is actually more important then using your kite to "hang in the air", in tacks yes, it makes everything much easier when you get the correct timming with the kite.
This is something many says - but I have the opposite experience, keeping the speed moderate and the timing spot on works much better for me - speed is NOT good as you will fail much easier now for many reasons.
I am talking about "surf" jibes, meaning carving around first, and then switching your feet just before or when you are headed up on the new tack, just like on a waveboard or windsurfer
Maybe we are not talking about the same kind of jibe, and if doing a racejibe switching feet first going into the carve, speed is good ?
I use the kite way more doing surf jibes than I do race jibes. It takes me a split second longer to get my body and feet in the right position doing surf jibes and the additional lift from the kite helps staying on foil. I don't practice surf jibes nearly as much as race jibes, so that probably has something to do with why I'm slower.