Why won't smaller, more efficient chips be usable as miners?
I just told you twice. They do not remotely compare to Bitcoin ASICs, and you only want see the magic "SHA-256" word.
We have a professor of Comp Sci who says they will be.
Hilarious.
I'm aware they won't be as powerful, per unit, as mains-powered ASICs. (Although they will be more efficient in hashing per watt.) They're mobile chips. That's not in debate.
"Columbias Sethumadhavan says custom ASICs may soon face a challenge from chips for mobile devices with circuits dedicated to performing encryption operations. These chips, expected next year, will probably be designed to a standard higher than the miners can reach and could be used to build powerful mining rigs without ASICs."
http://www.technologyreview.com/news/508061/custom-chips-could-be-the-shovels-in-a-bitcoin-gold-rush/(Sorry, he's actually an Assistant Prof of Comp Sci. My mistake.)
EDIT - we are not just going by this one MIT article. We followed it up.