Not on Macs. Some time ago, I got a nVidia card that was supposed to be an improvement over the old Radeon card I had, and it was, but only in some cases. In the worst case, it was 50% SLOWER. Sent it back and got a newer Radeon instead, which was consistently faster in all cases. It's probably drivers rather than hardware, but that doesn't make the problem any less real.People get eGPU to have Nvidia cards, not Radeon. Best render engines runs on Nvidia.
Anyway, yeah, I can't see how the price is justified. The Vega 56 is $400 (I know, I have one; the crypto mining inflation is mostly over and the prices went back to normal). So $800 for the enclosure? There simply isn't nearly enough there where that makes any sense at all.
--Eric