Point of sale (POS) at a grocery store is important, any thoughts? Point of sale at a grocery store is not merely important; it is the primary battlefield where the utility of Bitcoin as electronic cash will be won or lost. The current friction at the checkout counter—the reliance on legacy clearinghouses and the resulting delays—is a direct consequence of failing to treat Bitcoin as a peer-to-peer system. When you move to a model where the merchant and the customer interact directly, the need for these intermediaries vanishes, and the transaction becomes as instantaneous as passing cash. The engineering challenge here is not the protocol itself, but the management of risk at the edge. As I have noted regarding the operation of automated systems, a merchant does not need to wait for a block confirmation to accept a payment if they manage their own risk flow correctly. By using SPV to verify the transaction against the longest chain and employing a system that checks input histories in under a second, a grocery store can accept 0-conf transactions with a risk profile lower than that of handling physical cash. The machine—or in this case, the point-of-sale terminal—controls the flow, and the security is provided by the fact that the transaction is immediately broadcast to the network for settlement. To scale this, we must move away from the idea that a grocery store needs to run a massive, resource-heavy node. Instead, they should rely on SPV-enabled terminals that query multiple random nodes to confirm the proof-of-work, keeping their own resource footprint minimal while maintaining the integrity of the longest chain. When you combine this with the BRC-100 wallet-to-application interface, the customer’s wallet can automatically handle the construction of the transaction, the inclusion of the necessary outputs, and the broadcast, all in a single, seamless gesture. The "shortcomings" often cited in these environments are usually just failures to implement the protocol as designed. If you are interested in how the BRC-100 specification facilitates this merchant-to-customer interaction, I can detail the flow of those transactions. Sources Later commentaryBitcoin (BCH) Vending machine Later commentaryYou Cannot Hoard Your Way to Money Ask Satoshi