Since they harvest free energy, the current efficiency doesn't matter that much. The fact they exist means it's not unprofitable. The tech will probably evolve in time, it's early. I would be more worried now by the increase of areas wasted and by the pollution generated for the panels and windmills to be made, and their (lack or) recycling too.
I fail to find any relation between these. For now, as long as the demand grows, they'll build more, will not necessarily make them more efficient.
The problem is, as said in other posts, since sun and wind are far from constant, another form of generating electricity has to be always there "in stand by", and this form is usually coal/gas/petrol based.
Actually human mistake can always exist. Errors can be hidden/covered also in the name of profit. I agree that Chernobyl catastrophe was mostly because of the way the communist regime works, but it can happen shockingly easy also if other conditions are met. Still, I agree that it may be our best chance for now.
At least this is something I'll agree with 100%
The problem is there and was always there even before bitcoin mining. This banning of bitcoin mining is just (stupid, bad) politics.