At my home and relative's homes I've never seen anyone using a pressure cooker to boil water (to make it safe for drinking). They just take an ordinary steel vessel, fill it with tap water, add some salt and jeera seeds, cover the vessel top partially with a lid and let the water reach boiling point.
I just realized that it might be far more efficient to boil water in a pressure cooker until the first whistle sounds, since it's a closed environment that would lose less energy to the environment. It may boil the water faster (less cooking gas consumption), boil it to a higher temperature (greater variety of bacteria dead) and perhaps lose less water to evaporation. Is this practical or are there downsides to this technique because of which people dont use it?