There really isn't anything janky going on here, it's a poor lack of communication on the part of the spotify program and lack of understanding on the part of the user.
As for Spotify, as a long time user I love it. Very much worth a try.
You can signup with an email address , but the option is hidden quite low in the signup page.
Best way to avoid this sort of stuff is just to sign up to spotify with throwaway email.
I have found that it's worth buying a domain name and just tying it to a VPS with SMTP installed (or using a third part service that offers unlimited addresses). That way you can just generate throwaway email addresses as you need them.
You can also use Mailinator[0] and their many other domains for throwaway email addresses. In fact, you can point your MX records to mail.mailinator.com for a custom domain without running a VPS.[1]
Not necessarily. They also give you a “gibberish” address to the account. So if I use “foobar” as my mailbox on mailinator, they will list an address like M8R-wk43th@mailinator too, that does not let people log in.
Sounds like it's no longer required, but I suppose I still don't trust them enough to try their service.