I'm always rooting for velomobiles, though I feel like 91 kg is a bit too heavy for what this is. Supposing we start with a cargo ebike for comparison, a RadWagon 5 weighs in at 39 kg and has a comparable battery capacity, motor, and payload rating. This velomobile will likely have a sturdier recumbent frame than the upright cargo bike frame, and of course it has the fiberglass fairing.
But a difference of ~50 kg seems just too much. 20 kg would be plausible for a fairing, and maybe add another 10 kg for all the drivetrain component changes, like a more-complicated steering assembly and that third wheel. But where is that last 20 kg?
And I don't think the question is irrelevant, as one online reference indicates that existing velomobiles fall in between 20-30 kg. So this 91 kg behemoth -- even considering its cargo capabilities -- is very much the odd-one-out. The remaining weight difference is akin to carrying a second velomobile onboard the first one.