Is Bitcoin a threat to humanity?

No more than any other fiat money/currency: What is Fiat Money?

A bit coin is only worth what someone is willing to pay for it.

A fiat currency only has value because people believe that they will be able to trade it for products they want and for Bitcoin and other cryptocurrencies the same is true.

But the reality is that a $10,000 bill (if there was such a thing) is still, in reality, worth 0 cents which is what it cost to make the bill because it cannot be GUARANTEED to be worth anything really.

A lump of steel has genuine value because it can be used to make something or sold to someone else who can make something from it.