Orphan blocks are common, one block has never been considered secure. Early in Bitcoin, a best practice emerged to consider six blocks secure. So that takes an

Orphan blocks are common, one block has never been considered secure. Early in Bitcoin, a best practice emerged to consider six blocks secure. So that takes an hour, best case. (Given the insane hash power now maybe that standard can be lowered, but on the other hand it's not common to get a spot in the next block anymore.) So point of sale was never a good fit for Bitcoin. What most real world merchants do when the amount is small enough is to eat the risk. Even if it's easy to double spend in practice most customers won't bother for a can of coke.