With iOS 15, and macOS Monterey, you can send video and audio from your iPhone to your Mac, just as you already can to an Apple TV.
Sometimes there are new features in Apple’s operating systems that feel like Apple is slowly catching up with a wish list. From its origins as AirTunes in 2004, through its launch as AirPlay 2 in 2018 and on to now, you have not been able to stream video from an iPhone to a Mac using AirPlay.
Now you can. So if you’re by your Mac when you get a video sent over Messages, you can watch it on the big screen.
Read more at AppleInsider.com