I'm not obsessive about energy use. I just don't like unnecessary waste. The problem here is that wasteful engineering gets popular, and in software, all that waste is multiplied by the numbers of users. Both of those factors add up to significant carbon footprint, and also significant drain on mobile devices. The former is an environmental/social concern, the latter is what makes your devices last less on a single charge, what makes them lag, and what makes you able to run less software in parallel. Computing resources are a commons too.