I think inline preview and editing a PDF are addressing a feature that many users miss on the iPad-Version of Evernote.
Direct view and directly annotate the dokument without switching the app.
Most people I know, use Evernote and goodnotes together.
evernote: better to oraganize und find something
goodnotes: better notetaking, preview, handwriting and Apple Pencil support
Why not bring two good things together?