That's certainly a valid point on the trade-off curve to choose. But you could make a similarly reductionist argument about free speech, guns, home chemistry sets, etc. I think the position that "money is too important to be open" is a potentially reasonable one!

But what I don't think is particularly defensible is the position that the gatekeepers of our monetary system should be the corporations who happen to occupy the current choke points. And I think if you wanted to build a democratically controlled financial system that doesn't have corporate gatekeepers, you'd actually want to start with something very much like a decentralized open blockchain. That is, if you want to build a democratically controlled permissioned system, you need to start with an open fabric, and place the gatekeepers and choke points with intention.

Personally I prefer an open fabric, but I do understand the appeal of walled gardens.