iTunes Library must be played either from macOS or iOS devices.Unless iTunes Match/Apple Music is used you cannot command HomePod to play it; or am I really missing something here??
I don't command my Homepod, I have voice recognition turned off. The wife and I only play music via macOS and iTunes. Our usage is pretty simple, a wireless speaker that has great sound!
Although, I can understand how other people are disappointed with the offerings the Hompod don't have.