The Lightning Network implementation will soon be ready and merged into Bitcoin Core, which will scale to millions of instant transactions a day.

Also today, most on-chain payments are practically zero-conf. You can do certain heuristics in the network to anticipate double-spending attacks. Bitpay (a payment provider service) does it like that. Though it's not 100% secure (e.g. so-called Replace-by-fee attacks), it comes close.

Basically and all in all in the crypto-currency and blockchain world, we have several different consensus mechanisms today. One is not better than the other. They all have their specific advantages and drawbacks.