Elon Musk talked about how BTC mining with electricity isn't environment friendly but he invented electric cars, in near future if this actually becomes popular electric cars will be available world wide and billions of vehicles will be charged by electricity so how is this environment friendly?
He pointed that to the mining industry which powerup its mining by coal. So, as long its use green energy its ok for him. But tbh, its hard to maintain mining with that pricy green energy, so it will hard to get rid of it.