Ok, perhaps you can help me understand, as I am really stuck on this one. Is it possible for a toaster/phone + mining chip to be as/more efficient than the best ASIC's on the market ?
Absolutely yes. Phone, maybe not. That's more of monetization play, and a long shot on creating a distribution vehicle for micro-BTC that could be used for micro-payments.
But for any device that produces heat (toaster, portable heater, hair dryer, clothes dryer, towel warmer, dishwasher dry cycle, etc.), the efficiency of mining is infinite.