...and what happens if the bank representing the payor and/or the payee refuses to honor that check? There are chokepoints aplenty that can be formed and used by the forces of evil in this nation.
A couple days ago, one of the YouTubers I follow (I'm trying to remember which) said that the reason the U.S. Constitution made stuff like the Post Office part of the federal government was so that you could communicate with anyone without needing the blessings of a zillion private companies along the way. No one but the federal government itself could deplatform anyone from things like communication and banking; and the fed's ability to deplatform is severely limited by the First Amendment.