If the less energy is consumed than it values less.
Bitcoin requires massive power to mine thus creating gold quality in a sense that its finite and not easily achievable. Steem in other hand does not require lot of power to generate and as such it is valued less.
Why is the cost of BTC so high? If it was as easy as steem than everyone would be able to mine and get their own BTC and would certainly have less value.
That´s part of the current view on things in our world but to be honest it´s outdated in my opinion and maybe those new technologies we got could finally allow us not just to change the way our world works but as well improve the human threat towards nature.
In the end it´s actually not the work you put in to produce something but the faith of the people in its value. So changing the way we think about it could change the whole game.