[x] doubt.
For Meta to get access to any of the data, it’s users need to follow users on other instances. While Meta is a cesspool of a company that absolutely would love to have every bit of info about you in order to build an advertising profile, I do not believe that is what they are doing here as this would be inefficient.
Making Threads compatible with the Fediverse is likely more about addressing the challenges of a two-sided market, that is, matching users on one side with content on the other side.
Threads would have launched with next to no content. The Fediverse has tons of it. All of the folks I follow on Twitter have moved to Mastadon, for example. By participating in the Fediverse, they have content to provide to new users, and they make it easier for users to find each other.
That being said, fuck Meta and fuck Threads.