Cryptocurrencies and Current Money

In the US, when could crypto run into trouble with existing law on private currencies?

I believe it arises when crypto or stablecoins become defined as "current" or "lawful" money. This term was defined in State v. Quackenbush, 108 N.W. 953 (Minn. 1906):

"Whatever is lawfully and actually current in buying and selling, of the value and as the equivalent of coin. Current money means money which passes from hand to hand and from person to person and circulates through the community. It is synonymous with lawful money. Whatever is intended to, and does actually, circulate as money....Current money, that which is generally used as a medium of exchange."

The advantage to crypto is that the law prohibiting a private currency (from 1864) speaks specifically of metallic coins. (But, Congress could redefine coins.) Also, the OCC has described stablecoins as payment mechanisms and not money. (But, the Stable Act tried to define stablecoins as money.)

So, I am watching very closely on how the US Government defines stablecoins and crypto. Caveat: I am not a lawyer!