I'm not talking about their fake demo ads they put everywhere, I think they actually had an impressive in person demo using some different technology they couldn't miniaturize.
They had a few-hundred-pound cart-bound prototype called The Beast that was supposedly mind blowing to use, and that's what convinced a lot of engineers to drop everything and move to Florida to work on it. I agree pushing that technical narrative would have sounded much better.
I'm not a marketing person, but constantly alluding to something amazing without revealing details is a hack that stirs up a lot of curiosity and people discussing what it could be.
If you reveal the thing then that dies down (or worse knowledgeable people know that what you're dong isn't possible), but if you keep it secret while giving content-free little hints about it you can keep it going longer (and maybe raise more money by letting people in on the secret?).
I have a strong dislike for this kind of thing, but that doesn't mean it's not effective.
Even snake oil salesmen have a demo if they're good; these guys suck at being phonies.