I have always felt that IS is a bit overrated.
Try watching my wifes videos from her XT-20 then watch her video of the A7iii.
IS/IBIS has a useful function. Yes we use our cameras to video. It's extremely nice to take photos, mash the record... capture video and then switch back to photos all in the same fluid motion of holding the same exact camera.
Sorry video is not in needs.
For stills I agree. But for video the IBIS takes out so much jitter it makes it acceptable to watch videos SOOC using any lens of choice.