Excellent point. This also lends to it being easier for US tax subjects to use the dollar as a unit of account and ignore its (small, but not insignificant and always trending downward) value changes. I think a crypto wallet app that optimized for this problem would be super valuable, e.g. making doing taxes of these transactions seamless, and suggesting paying using a currency that is optimal for taxes (e.g. realizing a loss if that is possible, because then your purchase would come with a tax credit.) There are also efforts by legislators to enable de minimis exemptions for crypto transactions (taxes waived if the transaction size is sufficiently small)