i agree that most of the alexa skills are useless. they are junk. read them, they are like joke tellers or useless trivia.
but some are very useful. i think the key here is (as someone said above) we have 25+ years of GUI experience and about 2 of voice as UI experience. Give it some time.
A lot of these posts are mixing up alexa/google home and siri/phone. those are very different use cases. I don't like siri on my phone. i love alexa. we have three and use them all the time. but its about finding the right apps.
things we use them for all the time:
turning lights on or off
sonos integration!!! (right now this is a hacked version but native integration coming 2017).
alexa's native music selection is very slick
simple calculations and conversions
adding things to amazon shopping list (she is wonderful at this, too wonderful, i think they dedicate way too many CPU cycles to this vs. other shit)
however its the right apps. lots of those skills are dumbassed.
IMHO. I've been building apps for 35 years on every platform possible (mainframe, unix boxes, mobile devices, pcs, etc). I think the voice UI is going to explode. We are going to look back in 5 years and be shocked at the use of voice as a UI. again IMHO. your mileage will vary