Payment latency in crypto: is settlement speed really the bottleneck?

common narrative in crypto is that faster settlement times directly translate into better payment performance.

For example, systems with ~3–5 second settlement are often compared to those with ~10 minute confirmation times.

However, real-world payment scenarios suggest that settlement speed alone may not fully determine user experience.

In high-demand conditions (e.g. peak checkout traffic), delays can still occur even when the underlying network confirms transactions quickly.

These delays often originate from off-chain components, such as:

• Payment routing layers

• Liquidity provisioning

• Processor queues

• Wallet or API infrastructure

This raises an architectural question:

To what extent does overall system performance depend on off-chain infrastructure versus on-chain settlement speed?

In other words, is optimizing block time sufficient, or is end-to-end payment stack design the real constraint?

Curious to hear perspectives from others working on payment systems or infrastructure