By all customer accounts I've seen it was an expensive gadget that never worked reliably enough to be useful for anything, so hopefully they do better with glasses.
Of course, there are other ways to screw up (build quality, battery life, connectivity), but by eschewing anything fancy like voice control (ala Google Glass) they're signaling a certain conservatism that is reassuring.
Personally not interested in carrying an Amazon smart device with me everywhere, but it'll probably work for people who don't care.
It actually worked.
The thing is that it wasn't that useful and they never found product-market fit. Yet, it was an avenue worth exploring.
If you are curious you can find used Myos on eBay, see for yourself. There is a world between them a leap motion for example.
I've seen multiple very cool live performance from artists using Myo