I experience exactly the same as you, whenever I use a "waxed only" board - the front foot position will wear the wax away very very fast, so you need to either use a thick (ugly) layer of wax, or locally re-wax the board many times during a day of riding
Also - your balance point and central power point is on the front foot, and almost always the same point when riding a surf shortboard (every move origins around here usually), so this point is much harder loaded, than the back foot.
And the back foot is also moved a lot more, according to what glide and cutback you want - so here you dont wear the wax off nearly as fast
But eventhough I like riding on a perfectly waxed board, I dislike wax of other reasons - one is the "hot car and wax melting and running", or the "wax gets on all your other boards and kites and stuff when stoved in the car".
And as I see it, it is not "perfectly waxed" for long, because we ride so much longer and heavier than when surfriding, especially if really choppy out there - it gets "worn" out fast
So a pad is my preferred front foot anti-slippery "tool"
When riding waves, it does not matter much if front foot a bit slippery or not, as you are in "balance" on the board so to speak, and you only need back foot anti-slip. when doing flat tail slides etc.
But when going out fast and choppy, or riding the board flat, OR if choppy in general, it is really
if too slippery...
Kindly, Peter Frank