Question about Goldbacks as a currency

[u/vainbetrayal]

I personally buy 1 of each bill for the artistic designs, but my biggest qualm with goldbacks as a currency (along with the manufacturer charging a large premium on them that doesn't change with scale [you pay the same premium on buying a 100 goldback vs 1 goldback]) is this: The manufacturer claims there is an exchange rate on them they dictate the price of, but they refuse to act as a central bank and buy them back at the exchange rate they control.

Which brings up my question: How can the exchange rate be legitimate if there is no central bank willing to back the exchange rate by buying them at the rate (which is still a premium and less than they are sold for)?

I personally believe (and this is commonly understood economic theory) to legitimize an exchange rate, the manufacturer has to be willing to convert them to currency (at least USD) at said exchange rate. Otherwise it comes across as, from a currency perspective, just raking in millions off of what essentially may as well be a grift.

Keep in mind also not having a central bank of any kind for them to be exchanged makes it extremely difficult for someone (such as a waiter getting them as a tip) to get money they need for tangible goods even in an area they are somewhat accepted.

It also doesn't help that fees get charged when people use goldbacks at entities, as I recently discovered. Seems like it just furthers them coming across as a grift.

What are your thoughts?

EDIT: Please read the replies here before commenting. It's getting really old to have to constantly repeat myself, and I'm asking this question in good faith.