You won’t have a choice. If Tubman gets on the $20 bill, you must accept them (if you are a business owner or work for one). You could refuse to accept them in personal transactions but you’d look like an ass.
You think? Try paying your $2000.00+ property tax or your income tax with Ones or coins. Inspite of the little note on the front about all debts, you can lead the horse to water but it will be hard to make him drink.