How fast is this? I know I've always craved a "ai-based Magic Wand selector" for GIMP.

Someone will probably write gimp plugin for https://github.com/facebookresearch/segment-anything soon enough, there already is chrome extension https://github.com/kevmo314/magic-copy and figma plugin https://www.figma.com/community/plugin/1234171506421686729/M...