I'm buying it because Wave Race, FZero, 1080°, Metroïd, Zelda, Mario, Wario Ware, Star Fox, Kirby, Yoshi, Super Smash Brothers, Donkey Kong, Punch Out, Mario Kart, Pikmin, etc. are among the best franchises of the industry.
While most franchises tend to get old after x iterations (see GC disappointment), the revmote will make us rediscover these aforementioned games with brand new controls/gameplay mechanics. Nothing is more stimulating than buying a game and not knowing what to expect.
Besides, Revolution will likely be the console that will host the most new franchises and crazy japanese games. I saw Samba de Amigo mentioned in this thread and basically all Sega arcade games could do so well on Revolution. Sega must know that (right Sega?) and I foresee a strong Revolution support from developpers.
The Revmote controller will make Revolution the most polymorph console ever released.
You'll have the most diversity in game genres & control.
At this stage, there's no need to be a visionary to understand it will be huge.
Mark my words, Revolution is already cult.