I wondered that myself. In most books it just describes the font used in the book and since e-readers use their own fonts or the user can pick a font, it has no meaning and is deleted from the e-book. But in NOS4A2 the "Note on the Type" contains a real bit of the story. I think the publisher messed up by not including it. As an e-reader, I only know about it because I saw a copy of the real book, paged through it and read the final note.
I read the kindle ebook a month back and the story clung to me. But the exclusion of 'A Note on Type' is a travesty. I was able to find a hard copy at Kino in KL and read the epilogue in-store quickly. It sets up, or not, the next possible series of stories. As much as the upcoming IDW comics are prelude stories. It is a glaring omission.