Taylor Swift's Extended Play Beautiful Eyes is arguably her best work to date. I would be absolutely ecstatic if it could be included on Spotify. All her other music is on Spotify, so this album should be included as well!
The availability of music on Spotify is up to the artists and their music label.
If the music is unavailable, the artist or their music label may have decided to not make it available in Spotify.
Please check this Support article here for more info. :)