Before the Notes view we were struggling with the Overview page. We wanted to include information about the project, provide links to Google Drive folders etc. It was all possible but the we could not get the layout of the Overview page as we would like. It was (is) also impossible to review items from the overview page that were not in use.
So the Notes view now serves as our overview page and even more than that. We started out it with just one Notes page in the project but soon evolved to dedicated pages.
Project info contains all the information about the project. It describes what the clients wants, the solutions we offer, etc.
The People page contains information about everybody who is involved in the project (our consultants en the people from our client). When you need an e-mail address or a phone number, the People page is the place to go.
We also have a page called Links. We store links to our own Google Drive folders, to other cloud storage systems and to e.g. iAuditor templates from Safety Culture (which we use as checklists for risk analysis).
Invoice contains all necessary information to invoice the project.
All who work on the project can create an own note page. We use emoticons to mark the pages as personal note pages.
We find that using different Notes (as opposed to one Project Overview or Project Info) works well. It easier to find information and to keep it up to date.
We have tried a note page for “Extra questions for client”, but found that these are better kept in a task so that asking those questions becomes actionable.
We have a seperate project now, where have created several Notes pages as “templates”, so when we create a new project where will use these pages we copy the content of those “templates”.
It would be nice to have the ability to create these pages in a project template 
(As it would be nice to have more control over the views created when you use a project template).
That all notes pages are accessible by everyone attached to the project is not a problem for us. It fits in the policy that you give people access to a project (and all that is part of that project).