A lot of people who initially made their account with Facebook wish to deactivate their Facebook accounts, but if they do so they will also loose access and all data they got over the years of their Spotify account, since it was created using their Facebook details.
There should be an easy way to change your Spotify account, from a Spotify account which is tied to Facebook, to a Spotify (email only) account without deleting and creating a new Account, and especially without losing your listening history and suggestions - which is why a lot of people even use Spotify.