When someone gives 100,000,000 USD to someone else, that person’s bank eventually hires a bullet proof truck with two security guards with guns, and they move 100,000,000 of cash or gold to another bank. It’s expensive; it’s slow. I’m not a banker, I don’t know if they would wait for larger imbalances between banks before physical re-balancing of money. The point is, for large amounts, IOUs on a computer screen is insufficient. Physical delivery would be demanded. THAT is final settlement. It’s physical, and no-one owes anyone anything. It’s final.
When someone buys coffee with a VISA card, the transaction happens immediately. No physical delivery happens. Just numbers on a central computer somewhere. Someone’s bank owes someone else’s bank a few more dollars. That’s fine, it’s not a big risk. Who knows when re-balancing happens between VISA and merchants and their respective banks? It doesn’t matter. The point is it’s not with each sale, but aggregated. And the eventual re-balancing requires an armored truck, and it is slow and expensive.
A bitcoin transaction is as secure and as final as delivery with an armored truck from one bank to another. In fact it is MORE secure. Especially if you wait 6 confirmations (around 1 hour). More on that in the next article.
A lightning network (LN) transaction happens instantly. It is, to simplify, pretty much like a network of bitcoin IOU balances, with no interaction on the blockchain. (Exact details are beyond the scope of this article, LN is changing rapidly, and info is easily available online.) The LN wallet balance can be recorded on the blockchain at anytime if desired. LN payments are not as secure as the bitcoin blockchain, but that’s the trade-off for speed. It is an acceptable trade off, especially for small payments. It is as secure as VISA though, perhaps more. If it is not acceptable, you just use bitcoin and wait a bit more. The choice is yours.
LIGHTNING NETWORK is a second layer on top of Bitcoin. (VISA is a second layer on top of FIAT Cash. Both are fast.)
BITCOIN is final settlement of money, and incredibly secure. (An armored truck delivery of cash or gold is final settlement and on par, but not quite as secure as bitcoin.)