Bitcoin is for buying and selling, not for paying with.

From what I hear, it has a limit on the number of coins that can be made (aka mined). Which will keep the price high.

The record of how many and who owns what is contained in a string of bytes that everyone has access to. To get coins for free PCs do an obscure mathematical calculation. Called mining. Which in the process chews threw the records (block chain) for the rest of the owners. People had whole warehouses full of computers just mining away. I suspect it is not cost effective now.

Apparently stolen paintings are traded among the criminal fraternity as currency. I equate the concepts because paintings have minimal intrinsic value, but command high prices because they are "wanted" for the price they can command.

BTW - perhaps I should have said Wells Fargo not Pony Express. Or even "courier". Telegraph killed the Pony Express. But in the 19thC you couldna carry stocks over the wire, only the promise to pay! Modern money exchanges work to the millisecond.