Ahh damn. And here's me using bitcoin as a currency for over 5 years, not realizing that it can't be used a currency.

To expand on the quote of mine that BHC has given in the first reply: One minute, or even sub-minute blocks, do not solve the problem you are proposing them as a solution for. You can use the following equation to calculate the probability of not finding a block within a given time frame, with x being equal to how many blocks you would expect to find within that time frame:

P = e^-x

Let's say, for example, we drop the block time to 1 minute. e^-1 gives a ~37% of not finding a block in a minute. e^-3 gives a ~5% chance of not finding a block within 3 minutes. So for 1 in 20 sales, you will still be waiting at least 3 minutes (and perhaps much longer) for your first confirmation. This is unacceptable for most point-of-sale transactions, where there are a queue of people waiting for to pay.

Further, you now have to consider chain reorgs. As explained above, competing blocks at the same height, stale blocks, and reorgs of >1 block all become exponentially more frequent with a shorter block time. And the security of each of those 1 minute confirmations is only one tenth of the security of a current confirmation. You would need to wait for 10 confirmations to reach the same level of security. So even although 1 minute confirmations are already too slow, merchants decide they want to wait for 3 or more to be sure their confirmed transaction isn't suddenly reversed. So now you are waiting even longer.

The solution to this is either for the merchant to accept zero confirmation transactions for smaller amounts, or to use Lightning. Reducing the block time doesn't solve the problem.