I think it's because of the talent behind the songs, and the lyrics. Some फिल्में use iconic संगीत like Tchaikovsky's. He made some of the most लोकप्रिय themes in all of classical music. They also have award-winning composers like Arnie Roth. Other times, they use teams of writers who have worked together before and can come together and make great songs (The Rock 'n Royals soundtrack).
There are also beats that make आप want to sing and dance. आप could listen to the बार्बी as Rapunzel संगीत to relax, and the Princess & the Popstar संगीत if आप want to party! If आप want something funny, listen to The चूहा Song from बार्बी as the Island Princess. संगीत for Christmas? Listen to the Perfect क्रिस्मस and क्रिस्मस Carol soundtracks. Then there's the lyrics. There are inspiring songs like "I'm On My Way", "Only A Breath Away" and "Making My Way". There's probably a बार्बी song to suit every mood, and I think that's why they're melodious and touching.