Why have they made this video? I realise it's some Tuber making it but they've cooperated enough to suggest they were keen for it to happen.
There's a fair amount of 'debunking' that they've answered, but do they really need to? The proof of the pudding, after all, is in the eating and since they are well on the way to that they presumably have funding in hand. They don't need to answer all those willing it to fail, or 'proving' it can't work - eventually they will do a real demo or even an actual launch. Or not. But either way I can't see why they have to do this now.
Maybe they need more funding, but surely the answer there is to refute all the debunking to their potential funders, not the Internet at large. And, ISTM, if they really need to convince people it's a goer, surely keeping their wick dry until the last moment would prevent those debunkers having time to think up different reasons it can't work.