CO2 fire extinguisher after seeing people talk about them here. I'm still working out how to use it safely though i.e. to manage the risk of suffocating myself and others in a CO2 cloud. This seems to be highly non-trivial. I'll look for proper training once Covid eases off a bit.
The conflict might just arise from the fact that CO
2 extinguishers are more effective indoors than outside. I've had training on both powder and CO
2, outdoors (Did 7 months unarmed service at an airport fire brigade, as radio operator), and there is an art to putting out, say, an engine compartment fire, with CO
2. The general idea is to just open the bonnet enough to get the nozzle in and burst away. We also had an open "fire tray" of roughly 1m square with diesel sprinklers and a propane pilot flame. When turned to 11 it was a bit of a challenge with CO
2. But I did it.
Anywhere you want to keep going after taking the fire out, CO
2 is preferable, of course, because the cleaning from having used powder is going to be more expensive than the damage from the fire. Best example is the kitchen, with electronics a good second.