John Gruber posted an interesting tweet yesterday regarding how important the aesthetic design of a product is:

We’ve always judged cell phones by how they look, and we keep them in our pockets. Wearables — glasses, watches, anything — can’t be ugly.
— John Gruber (@gruber) January 6, 2014

Of course, some folks aren't interested in the design of a product, but in general it holds true. Some of the appeal of the iPhone is how stunning it is to look at. Part of the appeal of the Moto X is how clean and simple the design is while still being highly customizable.

So why is it that a large number of wearable devices just aren't elegantly designed? I see a few obvious reasons.

Physical limitations - The physical limitations of putting certain sensors, certain screens, and certain features into a device with a battery that can power it is challenging. Very challenging. In many instances, there is no choice but to make the device thicker than is desirable to accommodate the necessary battery, our battery technology simply isn't that good yet.
Unique design - The easiest way for the general public to judge design is if it looks like a product that we know has been beautifully designed. The problem here is that companies can't just all copy one another's designs or things would be very boring. Companies branch out, they try to put their signature mark on the product, and often it just isn't quite right.
Branding - Certain companies cannot resist putting their branding all over a device rather than letting the device speak for itself. The most glaring example is the new Pebble Steel with the large "Pebble" printed right on the face of the watch.

I'm not sure where this leaves us. I don't see any products out today (including the rush of announcements at CES thus far) that I believe will go mainstream, though some will likely sell fairly well. I do know that I've largely stopped wearing my Pebble, I remove my Jawbone Up for any half way formal event, and I wouldn't wear Google Glasses outside my house if I did own them.

I look forward to the wearable revolution, but I am seeing the M5 in the iPhone 5s being more and more valuable as the tracking mechanism of choice since it is beautifully designed and already guaranteed to be with me at all times.