Oh yay, going to start trying to call people out on stuff, right?
I have tried dual touchpads before. Touchpad joysticks are, for the most part, crap. And that's for two reasons. First, capacity surfaces lack the accuracy necessary to make it useful. And secondly, there needs to be some sort of physical indicator for where "center" is. With these in place, touchpads are perfect replacements for joysticks that also allows each "trackpad" to double as that, a trackpad. So we have something with a lower profile, multiple ways of functioning, and a lower chance of product failure due to a lack of moving parts.
As well, the use of slightly concave trackpad surfaces allows the surfaces to double as speaker diaphragms, allowing for a cleverly simple solution to adding in haptic feedback.
How about this... have YOU ever tried this Steam controller? Then how do you have any idea whether or not it's going to be a functional device? Do you really expect a company like Valve to make a decision like this lightly? If you haven't tried the beta Steam controller yet, then your opinion is just as much bullshit as the next person's.