The service here to replace Google Music. And that's the main reason behind the development of YouTube Music.
Therefore, many users use it as a method to listen to music for free without having to pay a monthly fee, as in the case of Spotify, and with fewer adverts. Just bear in mind that a great part of its catalog is made up of music clips and files that only offer the audio over a static image or with the song's lyrics. Taking into account the potential of YouTube, the online video streaming portal par excellence, it was surprising that Google hadn't decided to use to compete with other music services of the likes of Spotify or Apple Music.