I'll wait and see for a few reasons

When does it come out?

And can I understand anything about the game? I have no idea how any of the game mechanics work, but I would like to see Tidus, Wakka and Rikku!

I hate to be a bummer, but this game is also coming to the PS4. There isn't a lot of incentive to get this on the Vita over the PS4. It'll likely do well in Japan, but not so much everywhere else.

I am not saying that this will be Vita exclusive, but this game will be much more enjoyable on PS Vita than PS4 (who plays these games on PS4 tbh?). ^^

The people who have a PS4 but not a Vita, of which there are many.

Well, that depends on the person. Some people may prefer it on a console over a handheld, and vise versa. I'd prolly play it on the PS4, myself.

I have a feeling it will. Handhelds are stronger in Japan than consoles.

This doesn't really feel like a console game which is the only reason why it may sell well on the Vita, at least in the West. It feels like a mobile game, and not even a Vita or 3DS game. I mean it feels like something I'd play on my phone. Purely turn based combat has gotten pretty stale, and otherwise they didn't show enough to convince me that this game is worth even a $40 price tag on the Vita, much less the $60 asking price for the PS4 version.

I will say it's amazing that anything got announced for the Vita at all, much less during the actual Sony presentation. Between a Vita game getting announced, Shenmue 3 happening, and the FF VII remake announcement, I think Sony may have accidentally called on the apocalypse.

Kind of trolling, isn't it? How was Ninty conference and their spin offs and no gamez?

You forget Dragon Quest Heroes 2 -> it is also coming to PS Vita! 
Yeah I love the Square Enix support!

To be fair, if amazon listings are anything to go by, it's $20 less on Vita.