Almost overnight, Taylor Swift went from criticizing Spotify to singing Apple Music's praises. And the pop star is now revealing why.

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"Apple treated me like I was a voice of a creative community that they actually cared about," Swift told Vanity Fair. The magazine calls Swift an "Apple Music crusader" with the "willingness to take on tech giants."

A few days before Apple Music launched at the end of June, Swift posted an open letter criticizing Apple for not paying royalties to music rights holders during the free three-month trial. It took mere hours for Apple to reverse the policy, with Apple's senior VP of Internet software and services Eddy Cue tweeting, "#AppleMusic will pay artists for streaming, even during customer's free trial period."

Swift was apparently so impressed with Apple's...um, swift response that Apple Music became the first music service to count with the exclusive stream of her latest bestselling album, 1989.

"And I found it really ironic that the multi-billion-dollar company reacted to criticism with humility, and the startup with no cash flow reacted to criticism like a corporate machine," Swift added, referring to the response she received from Spotify after she pulled her music from the streaming service in November.

Spotify does have cash flowing in, however, generating over a billion dollars in revenue in 2014. The problem is its inability to turn a profit because it pays most of its revenue back to the music industry. Spotify says that its inception in 2008, it has paid $2 billion to rights holders.

Why this matters: The public back-and-forth between Taylor Swift and Apple ended in a happy truce. Apple was given the chance to show "humility" and that it cared about artists the same week that it launched Apple Music, arguably one of its biggest music projects ever. And by relenting to Swift's demands, Apple Music was also able to bring on board other artists that were once hesitant. It was a win-win for all. Well, except for "no cash flow" Spotify.

See also: Apple Music review | Complete guide to Apple Music12 top tips for using Apple Music | How to cancel your Apple Music free trial | Apple Music vs Spotify | How to cancel your Apple Music free trial | What are the differences between iTunes Match, Apple Music and iCloud Music Library?