Regarding distributing such documents, they are cheaper to distribute than applications. Regarding producing the documents, the author mentions Xanadu as inspi

Regarding distributing such documents, they are cheaper to distribute than applications. Regarding producing the documents, the author mentions Xanadu as inspiration, and in the linked wikipedia article we find rule 9: "Every document can contain a royalty mechanism at any desired degree of granularity to ensure payment on any portion accessed, including virtual copies ("transclusions") of all or part of the document.". So the idea for a mechanism to allow payments was foreseen. I guess there can also be advertisements, only not personalised. (Edited the Xanadu rule cited)