Okay, so I lied. The steam controller is not literally a waffle (even though the definition of the word "literally" has recently been changed to mean "not really literally," we all know this is bullshit (http://www.geekosystem.com/literally/)). And it's a good thing too, because it would probably be one expensive waffle.†
No, the steam controller is actually metaphorically a waffle. And here's why:
1: It's the same but different
The steam controller's overall form is very familiar, resembling something not unlike an xbox 360 controller, yet it has very different inputs, just as a waffle has a very different texture compared to a pancake, even though they're made out of similar stuff.†
2: It's customize-able
The controller is reportedly hackable and more customize-able than your average controller, just like a waffle in comparison to a pancake. Sure, pancakes can be molded into various fun shapes (like dinosaurs and Mickey heads, for people like me who have always wanted to bite chunks out of that cartoon mouse's skull), but can you make a pancake with this?
Didn't think so.
3: It can do things other controllers can't
Just like waffles can hold extra butter and syrup (or any other amazing goodness you can put on them) in their holes (huehuehue), the steam controller has the unique ability to use its track pads as either d-pads or analogue sticks. It also has a touch screen, one that's much smaller than the Wii U's.
So there you have it, the steam controller is literally (meaning not literally) a waffle. Lets hope it peacefully co-exists with other controllers, just as waffles and pancakes have peacefully co-existed for hundreds of years (excluding the bloody pancake-waffle war of 1532).
If you've made it this far, thank you for reading this crappy post I made as an excuse to talk about breakfast food. Damn, I'm hungry.