Well, normal human discourse isn't bound by the very specific rules of a courtroom.
I figured someone would suggest there's a gender issue at play in my distinction, and I think that's inevitable and unfortunate because I'd be making the same point if they were both men or both women.
Another factor I somehow managed to omit is that Musk's predictions are far enough off to be seen as aspirational, not statements of actual forecast. He said we'd have Tesla Johnnycabs by X date, but then no real movement on them happened, and self-driving proved harder than expected, and so far nothing has come of it. That's barker behavior. That's making noise to get headlines. I think it's still stupid and unserious and fundamentally not honest, but it's not fraud.
Holmes outright lied about what Theranos could do, and behaved (we now know) in ways that showed she KNEW she was lying and that the repercussions would be significant if Theranos was exposed, all while enriching herself from it. That's fraud.