You make too categorical a statement to put the burden of proof on the other. I don't know if you are referring to the last few months. If we take into account the trajectory of Bitcoin since it was created it is clear that it is the best safe haven against inflation. Look at how any financial asset has performed relative to inflation since 2009 and look at how Bitcoin has performed. There you have the proof.
In your argument which is more wishful thinking than anything else you are obviating the legislative problem. The way Bitcoin is regulated no one will use it to pay for coffee and small day to day payments because they will have to declare each payment and pay capital gains tax.