Bitcoin is a digital bearer instrument. It is a way to exchange money or assets between parties with no pre-existing trust: A string of numbers is sent over email or text message in the simplest case. The sender doesn’t need to know or trust the receiver or vice versa. Related, there are no chargebacks – this is the part that is literally like cash – if you have the money or the asset, you can pay with it; if you don’t, you can’t. This is brand new. This has never existed in digital form before.
Doesn't this reveal the flaw in the "Bitcoin is the solution to the Byzantine Generals' Problem" argument? My understanding is that the bulk of transactions costs associated with most payment systems is associated with chargebacks. Some result from fraud by the payer and some by the payee. Regardless, a digital bearer instrument doesn't eliminate these failure modes; it simply avoids them entirely. If the BGP is about solving the problem of fraud, then Bitcoin hasn't solved it. It's simply avoided it.