Good observations. The difference with Spectacles is playfulness and fun: kids goofing off for the camera on a beach vs normcore cyborg narrating on a bluetooth headset.
A potential weakness of Spectacles as a product is that it augments only non-selfie, "extraverted" photography. So it doesn't engage the selfie obsessed side of the userbase as much as the phone-based AR filters do.
I haven't been a fan of Snapchat, but now I'm curious to see how users react to this product.