The short answer is, fiat currencies are purposefully inflationary
The long answer is that Bitcoin has been made deflationary, due to a hard cap, coin loss, hoarding, or whatever. In the view of Gresham's Law, Bitcoin is good money to be stashed away, while fiat is bad money to be spent shortly. So whenever there is a choice to be made between what to spend and what to save, the choice is evident and straightforward, so there is no need to name it here
That's correct, except that we cannot apply Gresham's Law to Bitcoin. It only works with commodity money and only given that the price of both good and bad money is set exogenously. In our situation Thiers' law is more appropriate, which states the opposite to Gresham's Law.
I tend to agree to this gresham's law isn't that applicable for bitcoin as it talks only commodity money which on part of bitcoin isn't one of, Most probably the opposite of that will work on bitcoin. This is a non-ending discussion if both of you guys would not agree that bitcoin is only an alternative currency, just face check the reality of currencies. Ideally we can have a cryptocurrency to be used by the whole world, what's not ideal is that we are pushing it to be a non-centralized one, we are pushing too hard for bitcoin.