FuktLogik said:
As someone else pointed out, Disney's typical format for their animated films are essentially animated musicals. And in musicals, breaking out into song IS perfectly normal. It's how they tell the story, and Disney does a damn fine job of using songs to tell stories. Think about the first song in Beauty and the Beast.
See what they did there? They set the scene, introduced almost all of the main characters, explained the motivations of the characters, explained where Belle fits in, and set up the primary relationships and conflicts. All in five minutes. And not only that, they got all that across in an entertaining and engaging way. As Extra Credits has said time and again, people retain more when they are engaged as the absorb information. So not only does the song cause people to pay attention more, but they also remember more of it later. If not for the song, that introduction would have just been a succession of beatings with the expository dialog stick as they use plain conversation to explain who everyone is and what's going on.
And now, thinking about all that, look at the reprise of that song a little later.
They are communicating some abstract stuff there, compared to any of their other films. Ariel wants legs, Aladdin wants Jasmine, Snow White wants a prince, Pinocchio wants to be a real boy. Those are all very tangible things that are easy to explain. But Belle wants exotic experiences, adventure, and a change of pace from that typical life everyone else leads. She wants to see great things and experience all life has to offer. That's a little harder to explain. But, in that song, they perfectly encapsulate the emotion of what she's feeling. And if the words don't get all of that across verbally, then the triumphant roar of the music combined with the beautiful image of the vast forest fading into the distance will.
As for Monty Python, the thing about cutting someone off is a satire of musicals. If not for musicals, that satire wouldn't exist, and nor would it be funny. Like it or not, musicals are a very old a time-honored way of telling stories. And Disney has essentially revolutionized them by not only adapting them to animated film, but also keeping those wonderful elements of communicating story and character nuances in a neatly-wrapped song that makes musicals such a unique form of storytelling.