The Fediverse has 1 million active users. Threads has 130 million active users. This is not an EEE play because a 100% successful EEE play would amount to increasing the Threads userbase by less than 1%. Meta is doing this for non-EEE reasons.
One possible non-EEE reason would be to have plausible deniability for monopolistic practices. If they make a show of interoperating with irrelevant nobodies like us, they can pretend to be a nice tech company rather than a mean anti-competitive monopoly.