But a direct fund by the customer might not make sense, as I doin't think an owner of the coin is to be able to access the value without breaking the seal to get access to the private key.

If I understand what is being accomplished, no one knows the private key, not even the owner of the coin, until the seal is broken.  That way you are assured of value in the piece and this is not dependent on the integrity of the individual who had the coin created.  Even they can not access the value without destroying the seal Caldwell created.....

Therefore, a few steps are necessary to make this happen, but it is not rocket science....

yes?