Visually lossless means I couldn't tell an image difference even when pixel peeping with imgsli. Good enough means I couldn't tell a difference in video, but could occasionally see a compression artifact in imgsli.
The VMAF results are purely objective measurements. You can read more about it here; https://en.wikipedia.org/wiki/Video_Multimethod_Assessment_Fusion
Now there's a throwback to '90s/early internet humor.