According to Musk, these MMCs are not fully synchronized or audited "accurately," which can lead to discrepancies in financial data. He described them as "the biggest scam of all time" due to their ability to generate money without clear oversight, which, according to him, contributes to government waste.
For him, it's a scam simply because it lacks clear oversight; for us, it's simply because it prints money that isn't backed by anything.