Hmmm, might work in some spots.
Not here though, as we dont have big waves when sub or 10 knots, true.
But even the small half meter chop waves mostly always present will make it impossible to walk out to sufficient depth when dead onshore.
We also got sandbanks, meaning, that you will have to body/board drag between the banks where you can not reach the bottom - in order to get "free" so you have the room for starting without hitting anything.
As soon as up, you are home free of course - but you (I) need the extra room when on the verge to not being able to foil because of extreme low wind - it simply takes some downwind room and I dont want to hit the sandbank
The mast is 100cm, and the foils often curved downwards - so you need more than 110cm leverage to be free IMO.
Thats how many of our spots are around here, which is also good because no or hardly any rocks
But you are right - when a bit further out, or if flat water, you just use your mast/keel as an upwind dragging device straight down