My take is its a unique product targeting Vandersteen speaker owners seeking no holds barred ultimate performance from Vandersteen rather than mixing or matching.
It might well work great with other speakers as well, but it seems the group most likely to pounce are wealthy Vandersteen owners. Lots of competition in teh SOTA amp market otherwise.
Its a win/win for Vandersteen and their customers, assuming there are enough out there willing to shell out the $$$s.
Not to say other really good amps might not work as well or better, but those will not come from Vandersteen.