Bitcoin is a crypto currency that is acceptable to any other countries direct price, with out convert to equivalent price in USD, and secondly is faster than banknotes transaction, and secondly bitcoin transaction can be done at any given point in time, while Banknotes work with time duration.
I have a friend back in 2015 that was given a payment of 3.5 BTC. at that time it was $200 each and when the price went down to about $170 to $180 he sold it. What assurance can my friend get from there that he is not underpaid for his work?