Given that people have a tether between the board & themselves, and sometimes a cable from backpack battery to the board - why does the remote need to be wireless? A wired remote would be simpler, cheaper, fewer failure points.
I would argue the RF link is both more reliable and simpler than waterproofing and routing a cable solution.
Cost difference should be in the <10 EUR range. If you figure in cables, sealing and cable glands it might even be even.
No one said it needs to be wireless, but have you even seen anyone using a handheld leash on a foil board or efoil? You ideally want your hands free to help with balance and shoulder rotation through turns. Restricting this restricts your ability.
Not really. It would probably cost more actually and be more bother…
I don’t think it’s a good idea if you fall you could end up tugging really hard on the wire you could end up with the wire twisted around your body. Wireless remotes work so well and are really cheap. I have been riding for 3 years with the VX3 I had one fail but the functionality is great you get GPS speed, power, battery capacity, temperature etc…
After all that was said here, I estimate there is one use case that wired solution can shine - in the mouth. pushed by teeth or tongue.