Question about Astro HQ LLC Luna Display Astropad USB-C

With Luna Display, you can connect two Macs together, i.e. use one Mac as the main device and another Mac as a second display. It is possible to connect a MacBook to another Mac (e.g. iMac) as a second monitor, not just MacBook to iPad. The connection is made via the Luna Display hardware, which is plugged into the USB-C or Thunderbolt port of the main Mac, and the Luna software on both Macs is launched. The devices connect via the same network or by cable.

A direct connection of two MacBooks as two displays is technically possible by using one MacBook as the main device and the other as the second display. However, the typical use is MacBook or Mac as the main device and iPad or Mac as the second screen. The connection between two Macs works via the Luna Display app and hardware, with one Mac acting as the transmitter and the other as the receiver.

To summarise: You can connect two Macs with Luna Display to use one as a second screen for the other. The connection works via the Luna Display hardware and software, not only via MacBook to iPad, but also MacBook to Mac.