This is likely just an experiment rather than a full-fledged deployment. Low Earth orbit satellite internet would require a large cloud of satellites to provide significant coverage, similar to SpaceX's planned Starlink network. However, it shows that the company isn't done building its own high-altitude hardware now that it has stopped work on its internet drone.

Whatever Athena shapes up to be, Facebook's motives likely remain the same. As with Alphabet's Loon internet balloons, there's a strong commercial incentive to connect underserved regions. Even if Facebook doesn't charge a thing for access, it could benefit by adding millions of new users who'd view ads and use services (including through Instagram and WhatsApp). It would also look good to investors, as Facebook would keep its audience growing at a time when there's seemingly no more room to grow.