I'm pretty sure the intersection of people worried enough to remove the batteries from their cellphones and willing to buy internet-connected lightbulbs is indistinguishable from the null set.

As for their purpose, well, to the company it's too make money, to the buyers, that's explained by this classic¹ strip of C&H: http://assets.amuniversal.com/6e921050df960131725e005056a954...

¹ yes, it's redundant, I know