Interesting video and psychological play.

On one hand, those who know how much gold is worth either think your selling them a fake or it is stolen. Plus there's the "crazy guy (with an ugly t-shirt) at the beach with a microphone" factor. If the guy was dressed in a suit and tie, the people in the swishy neighbourhood might have taken him more seriously.

On the other hand those who don't know what gold is worth would assume that a coin is a coin and it could't be worth $50.

not sure what the parallel with Plexmar would be unless you are implyng that until Ucucha came along, the artisans and locals did not understand the true economic value of what they were puling out of the ground and that knowledge is paramount to Plexmar's success