The thing is, it's a natural interface with a decent interaction model. Keyboards, mice, etc, have all become second nature to most of us but they're still not truly natural. The Echo feels like one of the first voice-based interfaces that isn't a complete gimmick. And the hardware does an amazing job of perking up when I say the wake word and picking me out of a room full of noise.
What really convinced me of it's value was when I started digging in to writing a skill for it. My grandfather passed recently and my grandmother has horrible eyesight. I wrote a skill that enables my grandmother to ask to start a phone call. She is then asked who she would like to call. Once she says a name, she receives a call on her landline, is greeted, and the call is forwarded to the intended recipient. There was a small learning curve ("you can't just say, 'call John,' you have to ask her to 'start a phone call'") but it has worked and has provided an often confused elderly woman with poor eyesight a straightforward way of connecting with her loved ones.