the "only one monitor for your mac" constraint really reduced my desire to buy one
if i could have 3x 4k displays for my mac in Apple Vision Pro-land I'd buy one ez
It operates as its own freestanding device with its own processing/ram/storage etc. but it also can act as a second monitor for your mac (which is why I'd want it mostly) but only supports up to one "virtual" 4k display for now.
You can use VisionOS apps alongside the display but not more displays.