I'm sorry, but this is far from obvious.
> We can say that the worst case scenario for cryptocurrencies would be to share the same destiny as the BitTorrent protocol [3] where there is a lot of usage but is not popular.
Actually, the worst case is a crash and the whole scene collapsing in a mess of criminal trials and bitter recriminations.
Just because cryptocurrencies are 'legalised' doesn't mean a whole lot for the long term. In fact I would hope to see this sort of thing result in much more active enforcement of existing legal and financial protections, something the cryptocurrency scene has been unnervingly able to dodge so far.
> gaining territory
Not in many places. They seem to be seen by most folks I encounter as both passe (that was so 2017!) and basically as crimebux.
I'm also enjoying the frantic handwaving away of power usage concerns in the wake of the current rebirth of the green movement, post Thunberg.