Not necessarily. Thunderhead creations make/made kanthal 0.5mm x 0.2mm. And if you can't find it, make your own like @RuiG has done:
Hammer time!!!
I know @AngeNZ, but I'm too lazy in some respects to try and make some. And I'm a TC user who can taste Kanthal, which makes things more interesting.
@GeorgeS, was thinking that you should be able to hit somewhere around 0.5 ohms and the round profile makes for easy wicking then. But it's definitely in flavour territory though.