I also tend to hoard links. If there's a great thread on Haskell, for example, I'll bookmark it (save it to Pocket), with the intention of going back to the thread if/when in the future I decide to learn Haskell.
Ultimately, though, the problem is that whether or not I pay for this depends on whether this tool actually weans me off HN. If the summaries are so high quality as to get me off HN (except to post comments myself), I would pay $50 a month for this. If I still find myself reading threads by myself on HN, I wouldn't pay anything.