Great vid and well explained by the young lass . What a playground she lives in !

The foot tapping is clever in that the move prepares her to get her weight ( COG ) in the right spotover the foil before she transitions feet ... but it is happening subconciously as she makes does the drill .
As she comments , this is one technique ... mine is almost always to change feet after the gybe . Its from my windsurfing days I reckon .
Some friends swap before on one tack and after on the other as a rule , they ride surfboards like that too .
I need to be more symmetrical ...

I make sure I step off the back foot with some pressure ... not the front foot , this way the foil is on the rise slightly as I swap. Kite fairly neutral .
And for sure , as Kami says ... The swap always works better if my feet are both pointing in the direction of travel not at an angle to it .
After a bit you can also trust the foil will will keep flying forward without much foot contact on the board , so if its a messy transition for what ever reason , its best to avoid heavy contact while you get sorted to make the save . Sometimes just a toe..