The cost of a single Magic Crystal Card alone amounts to several dozen Gold Coins. If the demand is extremely large, perhaps the production costs could be somewhat compressed.
In an era of pure handcrafting, only Magicians were able to produce these items, and no matter how much costs were compressed, the prices could never be low.
To acquire customers at such steep prices, how many transactions need to be made to break even?
Not using Magic Crystal Cards and rather using more primitive accounting methods means that anti-counterfeiting will be the most challenging issue.
In order to imitate bonds using magical anti-counterfeiting techniques, all clerks must be replaced with Magicians. How many Magicians would be needed?
Even if money were no object to solve the problem of acquiring customers, that wouldn't necessarily mean customers would come.
