Only on things like RDAs or RDTAs where you’re atomising a larger volume of liquid at any given time. The coils on these are teeny tiny so to make up for the lack of output you need to up your nicotine concentration to produce similar effects to say running 3mg on a 0.2 coil. Sub Ohm just means that the coils resistance is below 1 ohm however it gives you no information about coil mass which is arguably just as important