I use a laptop. I use the two finger gesture to scroll, which leaves the actual mouse wherever it was last showing as the page scrolls beneath it. As a result, as often as not, when i scrolled a page the mouse would be activating an annoying popup when i was done.
In general, any UI where I feel like I have to play some sort of game of 'avoid the popups' while just moving the mouse around results in a terrible impression of the site. I was looking for a way to turn it off after less than a minute. Thankfully there was one.
I don't think it should be on by default, or even exist. If there were a clickable bit next to the link to open them that would be ok, and even useful, then I could click on either the link, or on the preview if i just want the preview.
But forcing me to carefully avoid leaving the mouse too close a link on articles often dense with links was just infuriating.
What possessed you to take an advertising technique (linking hover adds to keywords in content) that motivated people to adopt ad blockers and make it a part of the wikipedia user experience? I think there's even a wikipedia page about it...with some good advice:
https://en.wikipedia.org/wiki/Keyword_advertising
"Advertisers choosing to test this type will want to exercise moderation to increase Internet user acceptance."
Why would it say that? Because Internet user's really don't like playing 'avoid the mouseover popups', no matter what they contain.