:At one time, I thought the same thing, but I've since been made to understand that the purpose of this article was to be along the same line as the List of Final Fantasy VII Locations page and the other FF location pages  and, indeed, this article links to them at the top. It's simply entitled "Spira" because there's much more depth to FFX's world in making it and its locations feel like a real world, rather than simply a place with a bunch of locations on it where a couple of games take place. 

 :In other words, the Spira page wasn't intended to be a catch-all for anything related to the world of Spira that may or may not fit anywhere else, but, rather, it was merely intended to be a list of locatiosn from FFX and FFX-2, but it comes across as something much deeper than that because of how much more depth there is to this game's world. It's called "Spira" instead of "List of FFX and FFX-2 locations" because the concept of this world having a name is pushed forward much more profoundly than in the other games, with the possible exception of Final Fantasy XI, whose location list is also appropriately entitled "Vana'diel" instead of "List of FFXI locations." 

 :Sure, FFVII's world (Gaia) has a name, but outside of the location called "Gaia's Cliffs"  and a promotional pamphlet for Advent Children handed out at E3 in 2004  there's no significance for this name as far as the locations go. For all it's actually made relevant, the planet may as well not have a name, and most fans dont even know it does. FFIX's world (also named Gaia) only slightly pushes more strongly where this is concerned, but it uses the name Gaia more as a line of distinction between it and the planet Terra than anything else. We don't even hear mention of FFIX's world being called Gaia until it's time for us to learn about Terra. 

 :With FFX, Spira is the name of this world with all these diverse places and cultures and it's a word that people use frequently to refer to the whole of this interrelated melting pot of diversity, not just something they might bring up once in a year to distinguish it from another planet. "Spira" is a word that entails a lot in its usage, bringing up all these places and all these different cultures and groups of people, whereas "Gaia" in the context of FFVII brings up the imagery of "That place where FFVII is set. I just learned it was called that the other day, actually." 

 :Anyway, that's the reasoning behind the name and why so many other things weren't incorporated into this page. As far as a link to the blitzball page goes, though, there's that FFX and X-2 navigation box at the bottom of the article that links to the various other FFX and X-2 pages (all the characters, as well as the blitzball page, the Al Bhed article, the Mythology of Final Fantasy X page, and even the official soundtrack page. So if you really just wanted to put the link in here with a brief mention of Spira, the info you brought up on Spira is really already in body of the article anyway, and there's links within the body of the article and at the end too. 

 :I hope this is an adequate explanation of the reasoning behind why blitzball doesn't figure more prominently into the article than it already does as far as its relevance to certain locations goes.