Saw this show this past winter in Philly with my older teen who has fond remembrances of the book (and who hated the movie), and it was a packed house, primarily younger people anywhere from tweens to thirties, who were very appreciative.
I wouldn't say that it makes BMC look like Hamilton, in fact, it very much had a BMC vibe to me, maybe the George Salazar character in both shows is played similarly, but the cast was strong, and Chris McCarrell is very strong, even with material designed for a juvenile audience. He was very likable and enthusiastic, and captured the vibe well of a preteen boy who is off on a monster-y adventure. It felt much truer to the source material than the aging up that they did with the film.
I can see this doing well with families in NYC who want an alternative to the Disney fare that is pitched to appeal to a younger audience. Honestly, I enjoyed it more than Anastasia, which I literally dozed off during, despite Christy Altomare's fantastic vocals. Will it appeal to the Broadway patron who is going to see The Inheritance or Betrayal? No, of course not. But with cheaper ticket prices, I could see it appealing to families who don't have the cash to shell out for two part Harry Potter tix, and who would like to see a family friendly show.