That seems like a bad image for the stuff the OP is talking about - large print high detail stuff - since it's so small, but the AVIF "acceptable" still, even at low res, seems to be clearly throwing away detail compared to the JPEG "acceptable". Look at how the JPEG preserves some of the body seam in the second "l" in RedBull, for instance. So ok, it's a quarter the size, but they aren't showing me how big an AVIF with the same detail as the JPEG would be.

They're just showing that it can do a less-offensive job of erasing detail smoothly to take filesizes down to tiny levels than WebP or JPEG? But "tiniest size with least offense" is VERY different than "best size with greatest detail."