Apple Music allows me to search within my "Library"

I've noticed that when I search in Apple Music I can choose whether to search the whole of "Apple Music" or just my "Library". Perhaps the option has always been there, but I only noticed it yesterday. It's going to be very useful.

(In the Android app the implementation is slightly obscure. The option to choose "Apple Music" or "Your Library" only appears after I start typing in the Search box.)