If there's wind then the wing will hold your arms up.
A windsurfing sail is in front of the whole rider. They have very limited vision through the sail.
I think the idea of the wing is to catch a wave then hold the leading edge in one hand while you foilsurf with no power from the wing, or do a downwinder where you use the wing to move between swells or to get back up on the foil if you need to.
I spend a lot of time riding swells with the kite depowered. It's still necessary to keep some tension in the lines to stop the kite falling. That little bit of tension is enough to add some power to the foil so it's a bit of a stretch to call it surfing.
I'm certainly not dashing out to buy a wing, but I can imagine using it on those 40-50 knot days when it's a bit silly to try and fly a kite.
When I first saw Wipika kites I though they were hugely expensive and a bit stupid. 20 years later ...