These laws are setup by the elite - so they will always be valid and workable, even in a "100% digital age". Whether it's:
1) Cryptocurrency - add "redeemed in lawful money" verbiage to the account information.
2) PayPal - add "redeemed in lawful money" verbiage to the address.
3) Direct Deposits - the copies of a pay stub can still be indorsed with the proper lawful money verbiage.
Finally, a friend or family member can write a check and one can sign it with the lawful money verbiage. Only a few pieces of proof are necessary. Showing one knows about lawful money and has been redeeming it is the only true requirement.