Of course, they're as rudimentary an implementation of PPC as Apple could get away with/manage to kluge together! Apple had a near zero incentive to provide them at all and did so only because their established user base was up in arms about being left out in the cold when it came to running PPC ONLY Apps as they became available.
Apple, naturally, wanted its user base to buy new machines with beaucoups profit margins, NOT rinky-dink little upgrade cards with incremental $ involved.
Back on topic for a change:
ISTR that the Videovision/VideoVision Studio dates back to the IIfx era. I think that's where I'll wind up setting up my NuBus VidCap. I don't know which has the edge, VVStudio or the 8100 AVP Card, so I'll be testing that out in my Radius 81/110 before moving my VVStudio Card backwards through the time machine present in my menagerie of Macs..