I can attest that the IBIS on Nikon Z6 really made old lenses work. From a Questar 700 mirror lens to a pre VR 400 f2.8 I could handhold even over 12 pounds to vintage manual lenses.CFExpress is almost a bigger thing for me. Being able to unload cards that have 1700MBps read speeds and faster. And also having one format to invest in that has a future. IBIS might give my old 300mm f/2.8 non-is some new lif, a last hurrah for my first l lens that is pushing on 30 now. The video stuff I am sure some will find interesting but really that market is well served by the c line.
One caution is that it needs to know the focal length and vintage zooms won’t stabilize well as one zooms away from a selected FL.