The line "If you have a phone in your pocket, why wear this? And it doesn’t seem to replace the need to carry a phone." applies to both Glass and smart watches equally.
Both are wearable screens augmenting your phone, though the Glass has additional features, like voice commands and a camera
"If you have a phone in your pocket, why wear this? And it doesn’t seem to replace the need to carry a phone." is not a valid argument against google glass is what he is implying. The same can be said about pebble.
(for what its worth, Gruber backed the Pebble on Kickstarter: http://daringfireball.net/linked/2012/04/23/pebble-watch )