Speaking as an Echo owner, I've found that most of the apps I've found have been rubbish (translation: garbage). But that's not all that surprising: this is a completely new paradigm, on a par with WIMP. It's hardly surprising that
i) developers haven't yet really discovered what works well, nor have users discovered and popularised them; and
ii) the marketplace is flooded with junk, because it hasn't yet found a bedrock of solid, popular, useful stuff.
But it'll come. I keep my Echo in the kitchen, and setting a timer by voice is useful, if trivial. And I frequently use Spotify and TuneIn Radio to choose music.
I have little doubt that more will come in time. I think that voice control confirming the invention-hype-disappointment-delivery-equilibrium curve, and after a lot of users got acquired it as a Christmas gift during the hype phase, we're now in disappointment.
Similarly, people overestimate the impact of a new technology in the short run (which leads to the disappointment) but underestimate it in the long wrong. Voice will be no different.