Install for Updated Mac Apps
Apple brought many apps to the Mac with Mojave using Marzipan, which is a fancy way of saying they coded some popular iOS apps for the Mac.
With macOS Catalina, this trend continues. Apple offers up a new Music app and a new Podcasts app for Mac. They also are redesigning the Books app to make it look more like Apple News on the Mac.
If you live in these apps on your iPhone and iPad, and you are using the iOS 13 beta, it is a good idea to install the macOS 10.15 beta today to see how these apps work on your Mac.