I must be missing something here because I don't understand this thread at all. If you have closed throttle regenerative braking turned on you can still just open the throttle a little and coast (there is a place on the throttle where it's not fully closed but also not giving you power). Or maybe you don't have that function on the FX?
Yes, I know this coasting window, but it's far too narrow. Any road roughness will put the throttle position out of that band.
This setup allows you to completely relax your hand and get minimal/no regen, and then you can just rest the fingers on the brake lever to get maximum regen and braking lights so cars see clearly when you're slowing. This is much easier to work with for me, and seems to be more efficient because you can plan your regen better based on what's ahead.
Edit: Motorcycles slow down much faster than larger/heavier vehicles and the Zero isn't very aerodynamic, keep that in mind.
Mine is more aerodynamic and this setup makes a nice difference to me. I just lane-split a lot on my way home tonight, and a relaxed coast was a very helpful element.