I was looking for a tyre to use on the front of a semi-recumbent tandem, but according to the solid tyre manufacturer's specs, the max weight of the rider and bicycle must not exceed 150kg. So not possible unless my stoker and I lose 40kg or so (t'ain't 'app'nin').
The "equivalent tyre pressure" for this size of tyre is 80psi, which is way above my comfort pressure. On Marathon Touring tyres, we run at about 40-45psi.
According to the seller, they soften with use, and they are great!
But there are downsides-
Changing the tyre is a right royal PITA, so a broken spoke could mean the end of a ride.
They lack grip on wet surfaces.
They are not to be used on grass or gravel.
Sorry I even raised them as a possible.