I totally agree with you. Inasmuch as Bitcoin is important, especially when investing for the long term, that doesn't mean one shouldn't save in fiat, because there are other expenses that one will need fiat to cover. This can save one the stress of converting Bitcoin to fiat when money is needed and potentially selling at a loss. That's why people should always plan and not only think about the present but also consider the future. So one has to balance saving in Bitcoin and in fiat.
When Bitcoin as not comes existence, people are all saving in fiat, but since they have something much better then fiat, when they invest, they will get more profit on it. As for me, currently, I can’t advice someone to be saving or investing in fiat anymore, because I don’t see any reason of getting something big, but investing in bitcoin or saving, the price is volatile, and you can be getting better profit when your savings or investments is for a long term purpose. Investors always keep what they will used at that period and keep it in fiat and invest for Bitcoin, and that is the best thing as a experience people that really need something in future.