Agreed. It's not inherently a scam nor a ponzi since this rely on lying about how much money you have to pay back everyone at once. Btc is similar to artwork. There is no intrinsic value to it unless everyone agrees it has. Work is done to complete both and both are unique. Both are finite. Only 21 million btc will ever exist and only x numbers of paintings by this dead person will ever exist. If enough people believe both are valuable then their values will rise.