Yt music can be used by Chromecast.
Quality has no meaning in case of YT, as power of yt are unique playlists, search engine and content.
Availability of unique music is even more important than quality. For this reason I'm using tidal and yt music as two main sources.
Besides, quality of YT is not that bad as relatively good codec is used - opus. It is batter than ogg used by spotify and aac used widely by apple (also in case of air play).