The first is because the song is one of the most misinterpreted in Broadway history. I'm not saying the way singers perform the song is wrong. It's probably the best way to sing it as a standalone number -- wildly upbeat, an affirmation of determination and an unbeatable, joyous spirit, a song of eternal hope. I'm just saying that despite what most people think (who haven't seen the show), that not only isn't what the song is about, it's actually the exact opposite.
In Gypsy, the scene comes along when the maniacally driven, overbearing Mama Rose has finally gone too far, and her youngest daughter, known in their vaudeville act as Baby June, has had enough and eloped with one of the boys from the act. That's put an end to the act, since June was the star, and her supportive, older sister Louise has no talent and knows it. And they're largely out of money. And all the boys in the chorus have just quit. But Louise is thrilled by events, and so is Herbie, their manager who's in love with Mama Rose.
Together, Louise and Herbie realize that at last they can all have a family. Leave the road touring. Have a normal life. The act is over. Gone. And vaudeville is on the way out. This was the best thing possible. They have their life back!
Except that Mama Rose refuses to accept reality. And as they look on in shock, she begins to explain that the act is not through. That she'll resurrect it, but this time with the totally untalented, completely reluctant Louise in the lead. Mama Rose will train her to do what she is unskilled to do, and unwilling to do. But Mama will show the rest of the world, Mama will show June, Mama will show the boys who quit, Mama has her dream, and to hell with everyone else. She'll force her will on them.
And to the horror of June and Herbie, Rose -- oblivious to them, oblivious to the real world around -- almost feverishly sings that everything is actually wonderful, that things are swell, things are great. And all June and Herbie can do, standing there alone with her, ignored, can watch in stunned shock, even to the degree that June rushes to Herbie and buries herself in him, hugging him for the only support she can get. All the while her mother stands out front telling the world, crazily, that "Everything is Coming Up Roses." It's a song of mad, self-deception.
And the second reason for showing the video is that, in the movie, Rosalind Russell's singing is dubbed by Lisa Kirk (a Broadway star who was in the original Kiss Me, Kate) -- but in this footage we have Rosalind Russell doing her own singing. She's not great, but skilled -- in fact, she had starred in a Broadway musical, Wonderful Town -- and gives a perfectly solid interpretation.
And, of course, the proper, original interpretation. Not a hint of uplifting spirit to be found. This is the first step to a woman on the road to a breakdown.