Loads of dance music is defined by having a 2step beat, whilst you can find D&B, dubstep, breaks etc thats 4x4 most of it isn't, whereas most of techno is.
And of the types of music that go down the 4x4 route, I think techno is the most experimental and has the least conventions. Which is why you get monolake and joey beltram producing music under the same genre. You don't get the same amount of variation in other genres.
Anyway, its all subjective but for me its about a lack of convention and lots of experimentation, built round a 4x4 beat.
So yah boo.