This is actually pretty cool. Lately I'm thinking a lot about what a better SRS could look like. Currently the best one in my opinion is Anki, but I want something that is both simpler and more flexible.
I think SRS needs to be thought of as not an app, but a ubiquitous feature in all content consumption environments. This and the browser-extension feature the article mentions are interesting experiments in that sense.
I agree, but you still need a program / app to review and schedule your previously embedded cards, no? It would be amazing if there was an agree-upon data format for flashcards so that courses could provide them.