Most day-to-day cash transactions work perfectly fine using $20 bills.
See e.g. https://www.washingtonpost.com/news/wonk/wp/2016/02/16/its-t...
> [...] illicit activities are facilitated when a million dollars weighs 2.2 pounds as with the 500 euro note rather than more than 50 pounds as would be the case if the $20 bill was the high denomination note.