Square Enix is excellent in alot of ways, they have a very successful MMO (albeit there are some future accessibility issues since PSN & Square dont let you change accounts and the regions have to match for product purchases).Most of the value from Paramount IPs seem to come from the fact Tom Cruise is still working with them. Personally I would much rather have Final Fantasy in the long run over any of their IPs.
Final Fantasy is the perfect gaming IP to be adapted to other media. Just like it happened to Fallout or TLoU it's only a matter of doing it right once and it would go mainstream.
Sony can't see the value on PlayStation, can't see the value on SquareEnix, can't see the value on exclusives, but they can see the value on Paramount...
They also have Final Fantasy which is always a extremely high quality IP, Rebirth likely will wing Game of the Year and that will definitely get Sony's attention, amazing graphics, the combat, the HUGE world, incredible exploration.
Same with FF XVI which is just an Epic adventure where the main story quests in particular offer extreme highs. Final Fantasy alone is a Legacy IP for gaming as a whole
They have Dragon Quest and the connection with Disney for Kingdom Hearts. All three of these IPs are incredibly hyped along with the subscription based MMO, but they also have smaller IPs and games that can garner more & more attention over time.
Along with a Audience and balance that is missing in the current first party balance in RPGs and mind-blowing different kinds of stories & a huge + acquiring Square would give them huge attention and connection to the Playstation mindshare with its Japanese audience pretty much all year around.