0.6% is not a very large amount. Also, the proportion of renewable sources in electricity production is growing with every passing year. Why no one is talking about the environmental footprint of minting coins and printing banknotes? How much ecological damage is done by the mining of metals that are being used to mint coins? Also, how much forest is cut down every year, for printing banknotes? Once mined, Bitcoin is indestructible. On the other hand, banknotes and coins need to be replaced time to time.
The reason that no one is talking about it is because they have no relevance to their agenda which is to point out how bitcoin consumes a lot of electricity to operate. And if they talk about it in the same realm as bitcoin then they would end up dwarfing the amount of electricity that bitcoin compared to the ones that they put together with it. Banknotes that are out of commission can be used to make fertilizers depending if the bank note is made up of cotton or if it is made with polymer then there isn't a need to replace, it's not bitcoin against the world after all, they just want it to look like that.