faith/trust based yes, it ain't a ponzi scheme though. Bitcoin is basically created for the people, by the people who are tired of the trusting the Fiat/Cash that the government manipulates anytime,everytime, whenever, whereever they like.
you tell an exciting story about bitcoins to your relatives so they start buying it and you gain value on your coinisnt that how ponzi went too? tell me what is your real bitocin value ?