When combined with the Samsung SmartThings Hub and zWave light switch controls, the Amazon Echo, i.e. "Alexa" has become a very often used home automation interface at my house. My kids love being able to turn the lights on an off in various rooms in our house using just a simple voice command. And I must say, being able to turn the lights off at night by voice command after you lay down in bed is pretty sweet :).
There are some limitations still however -- Alexa gets a bit confused if you have a thermostat labeled "upstairs" and you have created a group of lights called "upstairs" as well. So you have to name things pretty specific prior to setting them up with Alexa ... and then the limitations of the human brain become the problem, because not everybody can remember those specific names you gave the devices!