macOS has been doing memory compression for years. Basically, apps and background processes that are idle have their memory compressed, and then upon exiting idle (due to user interaction, a timer firing, etc.), the memory is decompressed. The compressed memory doesn’t touch swap.

It’s possible that Apple Silicon has some hardware acceleration for doing this in-place memory compression, but otherwise it’s pretty old news, which makes this marketing shtick even more frustrating. 8GB was borderline not enough even back when memory compression was added to macOS (maybe ~10 years ago?).