The dependency on external feeds remains of course but you have control over your own blog, where you host it and what software you install there.
While one of the main goals of the plugin is to provide an infrastructure to connect to your friends' blogs and potentially exchange private posts with them, an important aspect is that it is a versatile RSS Reader (see https://wpfriends.at/consume-the-web-your-way/) that can be used with another plugin (like demo-ed) to then send new articles to your E-Reader (converted to .mobi or .epub).
Seems rather trivial to accomplish in whichever way you want:
https://zapier.com/apps/feedly/integrations/pocket
https://ifttt.com/applets/QfKPm8rx
https://pipedream.com/apps/feedbin/integrations/pocketI do wish the article would be more upfront about that.
That's correct but there are other e-readers that support a similar technology, such as Pocketbook, or the Arta Tech Inkbooks.
While not supported by the plugin (yet), many readers support syncing new content via services like Dropbox, therefore you could use a service that uploads file via e-mail to Dropbox.
Overall the workflow part of converting an RSS feed item to an E-Reader format (i.e. ePub or Mobi) is covered, it seems viable to add more delivery mechanisms. Due to the market I am in (Europe) I've investigated the possibility to deliver to the Tolino platform via libraries like https://github.com/hzulla/tolino-python, but also adding Dropbox might be a possibility.