But, with that said, it's not actually a high bar to clear. Advent Children and Spirits Within were both very meh.
This ties in directly with Final Fantasy XV and it gave some really good context for what is happening offscreen during the early events of the game. It is kind of weird that it's out so much earlier than the game itself but I suppose they're just trying to generate as much hype as possible before the launch of the main product.
It's definitely not required watching to play the game but I was super happy with the added context I got from it. I'm now much more interested in the magic system and political happenings in the world of Final Fantasy XV.
I don't want to spoil the story for anyone but if you're a Final Fantasy fan or plan on playing Final Fantasy XV I would recommend watching this movie at least once.