And screen readers would implement that by detecting a meta tag named "ms-application-jumplist"? In other words, screen reader developers should support proprietary Microsoft extensions rather than using the standard methods of supporting screen readers?
You're right, it's brilliant.
yes, what about screen readers? Screen readers get a well-thought-of menu of accelerators to existing features of the website. If the website is well coded, this can even be one of the website's own, displayed menus.
What is there not to like?
Instead, by embedding it in random meta elements, screen readers have to download the useless code (as does every other browser out there) and can not use any of it.