Sidecar is an obvious OS feature that I've wanted since the original iPad, and the third-party attempts/solutions from VNC to Remote Desktop to Air Display to AstroPad to Duet to Luna were not great and some of them added very annoying bits like subscription pricing (seriously?) or clunky/expensive hardware adapters.

I also considered how easy it is to have your iPhone screen show up as an video source in QuickTime Player, just by plugging in a lightning cable...

I'm deleting basically all of them (possibly excepting VNC, which has a few different use cases) and switching to Sidecar.