alt Hacker NewsIn this case in particular it looks like an acquihire.
Meta just saw two engineers actually execute on the joke about "building Facebook in a weekend" except that it then really took off in its target niche and generated a ton of press.
I don't doubt that they're interested in the AI aspect, but I suspect that a significant contributor was that they demonstrated competence right in the middle of Meta's wheelhouse so why not just grab these guys?
It's also part of their longer-term trend of buying or burying any company that starts to get any press as a social media site of note outside of major players where that hasn't been an option.