Apparently they flow from high-profile accounts. If someone can inject one message across so many Twitter handles, they most likely can inject other messages as well. Like ones tailored to manipulate the stock market, or impacting international politics.
And more generally, always question the authenticity of any information you receive electronically (email, SMS, PMs, websites etc.), as a basic security principle. "Are they asking for something valuable?". In this case red flags are obviously 1. bitcoin, 2. too good to be true, 3. why would these people just give out money randomly.
In the future the scope may grow to include visual and audio communications which could be faked using AI.