I don't know about "important" but I do think there are interesting problems it can solve. I would definitely like one.

A little quick analysis before I offer my answer.

As an ambient-presence, always-on technology, it doesn't solve any real problem. As this Gawker article (correctly, IMO) argues, it just makes you look like an asshole (HT, J L).

If You Wear Google's New Glasses You Are An Asshole

The reasons are similar to Paul Graham's arguments against the Segway (makes you look smug).

The Gawker article actually understates the problem by assuming it is a transient/early adopter problem. In fact it is a fundamental problem. Bluetooth headsets have been around for a while now, and people who walk around wearing them still come across as assholes.

But this doesn't mean the device is useless. Bluetooth headsets look quite normal when they are worn by people who are driving or people in specific active duty roles like security guards.

The key is active duty. If the device is clearly relevant to an active duty, it looks normal, otherwise it just looks self-important or creepy.

So given that analysis, and assuming no radical design changes, where would Glass look normal in its current form?

Here are some ideas:

1. In tourist settings, where the AR can tell you what species of bird or tree you're looking at, the details of the painting in the museum (replacing those audio-tour things). If you're a tourist in a place that also has normal residents, you should also wear shorts and a fanny pack to signal that you're a tourist.
2. In active gaming situations for non-contact sports. I can think of some really cool apps that might make it very useful for sports like ultimate frisbee. Like cueing me to run faster or slower based on real-time analysis of the frisbee.
3. Survey type activities with a need for logging, like a home surveyor assessing a house and taking visual/audio notes. Health inspectors, crime scene investigators... all these people who need to look at their surroundings with a specialized perspective can make great use of Glass.
4. For people doing specialized hands-on work with some telepresence included (like cooking or car repair or minor surgery, or search-and-rescue under the direction of somebody else, or when teaching somebody else)

What is common to all these situations is that:

• They are specialized situations
• There is an obvious answer to the question, why is that person wearing an AR device?
• The "creep" factor is automatically removed because there is no uncertainty about intentions

I'll also offer a thought: if Google (or a copycat) does want this to become a non-specialized ambient-presence type device, they should redesign it as a clip-on monocle on a chain. This works for people who already wear glasses or sunglasses. For normal sighted people, the thing should not look like regular glasses. Maybe it should look like an extended bluetooth headset or something.