And also, annoying for Echo device users, since the use of the word 'Alexa' will trigger the device, and thus mute/drop the volume so that you can't hear what is said next... I guess it could be worse, since the volume reduction means the device doesn't hear the command and try to execute it as well!
TBH, I don't understand why they couldn't add a circuit that checks if the microphone is being activated by the device's own speaker, and ignore it. Some sort of simple phase inverting circuit from the speaker that gets summed with the microphone input ought to do it. It's not exactly rocket science and they're doing complex phased-array/beam-forming stuff with the microphones already, so it's not like the engineers are idiots?