Every monetary system is based on a shared belief of value, therefore "faith". That does not mean that any cryptocoin is the same as USD. For example, there is no independent auditing to help assure me that Tether actually has the reserves they claim. And there is no transparent way to know where this money supposedly is, making it much easier to scam people than a traditional bank. If there is a problem with a bank, there are several legal and financial consequences for everyone involved, enforced by the government. The government also will, as it has, try to undo the mess even if it is at the expense of inflation or debt.

So yes, USD, Tether and my poker chips at home do share a fundamental characteristic of any method of exchange, a subjective belief about their worth that is ultimately decided by collective agreement. That does not mean they are anywhere close to the same thing, or scams.