The macOS Catalina Music app, which replaces music functionality from iTunes, offers two ways of rating your music: you can either use stars or “loves.” The latter binary option suits people who only want to flag their favorites, but the five-level option for stars is for those who like more granular judgments of their content.
You can go further; you can use half-star ratings as well. To do so, open the Terminal app in Catalina (it’s in /Applications/Utilities), paste this, then press Return.
defaults write com.apple.Music allow-half-stars -bool TRUE
You can then apply half-star ratings by carefully clicking on the stars when visible. If you click on the left side of a star, that counts as a half star; if you click on the right side of a star, that gets recorded as a full star.
If you want to turn this off, run the following command in Terminal:
defaults write com.apple.Music allow-half-stars -bool FALSE
Learn more about the new media apps that replace iTunes in macOS Catalina in my new book, Take Control of macOS Media Apps.