But mining gold is not as easy as bitcoin. Mining gold needs man power and also equipments. And you cannot just mine gold if you feel like to. There's a lot of process needed to be done in order to mine gold. You have to go through the government sectors. The damage that mining gold can cause in the environment, is much heavier than bitcoin.

You say, it cost 'less', but there are a lot of factors need to be consider also not just the cost.