Hi,
I notice that the feature also works on my watchlist. It is a little bit annoying because I move my cursor a lot on my watchlist to check several edits, so many hovercards appear for nothing. Moreover, as far as I'm concerned it is not useful on watchlists because I already know all articles I watch...
I don't know if many people asked for Hovercards in watchlists, but for me this is not useful, and even annoying on the long-term.
Thanks for this useful feature on articles anyway ! Regards,