It depends what "smart" actually means. Something like the Withings Activité [1] can afford to be a well-designed piece of jewellery because there is no expectation (or possibility) of software updates. This isn't true of Android Wear or the Apple Watch; models sold this year will become obsolete within a timeframe that is much shorter than one would want for high-end jewellery.

[1] http://www.withings.com/us/withings-activite.html