Jeff Benjamin, 9to5Mac, on what you can do with AirPlay 2:

• Quickly see what’s playing in every room on every speaker
• Play the same song, in sync, in every room
• Play different songs on different speakers
• Use Siri to play different songs in different rooms
• Stream to rooms without grouping speakers

Take the time to watch Jeff’s excellent video, embedded below. It starts with the basics of setting up a stereo pair, but then comes the good stuff, as he dives into the details of AirPlay 2. Absolutely worth the watch.