The key distinction everyone's hitting on is real, but Norway's probably also worried about the normalization factor. Once smart glasses become everyday wear like regular spectacles, there's zero social friction to wearing them anywhere - you blend in completely. A phone held up to your face creates an immediate "I'm recording" announcement, which at least gives people a chance to react or move. Smart glasses skip that entirely, so someone could be capturing your face, conversations, or sensitive moments all day without you ever knowing. That's a different beast than the privacy concerns we already navigate with phones.
The practical angle that might actually matter here: enforcement. You could theoretically require smart glasses to have an active visual indicator - like a light that's always on when recording - similar to how some dashcams have a small LED. That way the "inconspicuousness problem" gets solved without banning the tech outright. Norway might be looking at temporary restrictions partly to figure out whether regulation (mandatory indicators, geofencing, technical requirements) could work instead. It's messier than just banning them, but it lets the technology exist while addressing the actual problem, which is covert recording without consent.
The comparison to phones is interesting though - we kind of accepted that trade-off already. You can't realistically ban phones, so society just learned to live with the possibility of being filmed. But catching that tradeoff early with a newer technology, before it becomes ubiquitous, gives regulators a chance to set different rules from the start.