"I've never read the book so I went to see the show without knowing what it really was about. And I truly think they could have done more with Evelyn or leave her totally out of the stage production - she didn't have any important function considering the story. She just "was" there, to give the main characters a moment to rest. The part didn't require any great acting, nor great singing. Comic relief, maybe, but totally unnecessary one."
I guess then, you didn't realise that Mother's Younger brother was in love with her, and when he was rejected it opened his eyes to certain things, and made him bitter, lonely and sad. Therefore, she did have a purpose other than singing about her life.
Also, it was telling of the time period. The musical incorporated truth, and Evelyn's story was one of them. We saw how she grew to success, and we saw how she failed. If she was unnecessary, than Houdini was, too - which I totally disagree.
"Do you know what pledge time is, Andrew"? said the PBS Executive.
"Yes", Lloyd Webber replied. "My 50th birthday special must be one program that gets done a lot."
"No", mused the man from PBS heedlessy. "Not so much. Our Stephen Sondheim Carnegie Hall concert. That's a big one."
Spoons, forks and knives seemed suddenly to suspend their motion in horror, all around the table.