Cabin baggage? Not really an option with baggage limits!
So, on an average trip I'll be hauling around a laptop, phone, tablet, digital camera with 3 spare batteries, wireless headphones (with spare battery) and a couple of external batteries (you know, like those that EE lend to their customers). Add all that up and you've used up all the cabin baggage space. So, those things that I actually want with me in the cabin I no longer can carry...
I think a better solution is to improve fire suppression on planes, and for manufacturers to produce more stable batteries...