I just did a quick search on “flash bitcoin” and I couldn’t get anything useful from the results and when I checked YouTube I saw that it was something that I have heard about in the past.

Flash bitcoin is mostly used by scammers to pretend as if they have truly completed a transaction so as to convince their victims into sending them money and I believe that the set of people that will mostly be affected by it are those that don’t know how to confirm their transactions on the blockchain rather they just rely on screenshots from the sender (which I’m sure only few people do).

I don’t see it affecting the price/market of bitcoin, they have been cases where counterfeit fiats were being used to purchased things by scammers and it’s still being done. So the fact that someone was lazy enough not to check his/her transaction on the blockchain before proceeding with a deal does not mean that the whole market system will crumble.  And I do  hope the “flash bitcoin” I saw on YouTube is the same one you’re talking about because that’s what my post is for.