Considering how they presented the Figures as "Customized personal memory Card Character-based", and how the figures could appeal a younger target than the Smash core fans, I think that this is a good idea to push the figures in-store and in the houses of several customers, even the ones not so interested in them.
I think that they will be optional to the game, and that there will be LE aside the normal one.
So, if you want to play the game normally, you could buy it normally, play it without figures. If you like one of the figurtes, you can buy the "Link edition" of Smash, or the "Mario edition" or the "Charizard edition" of the game. Playing with that character, you can transfer its data and maybe other "stats" to the figures.
Then, in 2015 when they'll release "Pokken" you can use your Charizard figure on the Pad to activate "your" version of Charziard, maybe even with its stats, unlocking from the beginning it's Mega version in-game.