Is this better than just paddling, standing up? I don't see much advantage...
Standing up isn`t too exciting but the extra push for your legs is a big big help.Especially in a head wind. A little push with your hand sure makes a differance. Today I was at emerald bay in tahoe where the speed limit is 15mph. I was side by side with the other boats. I`ll have to get a SPEEDO.
I can see the benefits if you have a health issue that precludes pedaling. I can see it as a stand-up alternative to using a paddle, and I can see it as an add-on to pedaling in the seated position. On the other hand, I would question whether the stand-up use would be more efficient than using a paddle, and whether using a paddle as well as the pedals would have generate more speed than the arm-assisted pedal stroke.
Much of that would come down to the cadence rate at which the Mirage is effective and the strength of the driver. Since I don't own one, I can't say for sure, but I suspect that there is a sweet spot in terms of cadence to get the best speed out of the drive, and that additional pedal speed above that either provides minimal extra performance relative to the effort, or could even be counter-productive. That will likely differ for the different fins as well.
I find a smooth paddle stroke to be relatively effortless, so I would expect that I might be happier paddling while pedaling to either take a little pressure off the pedal stroke or generate a little extra speed.
In any case, if it works for you, it might work for someone else. It also might be the oddball idea that leads someone down a revolutionary path, so kudos for thinking outside the box.