You are correct, and the parent you’re replying to is confused. Nitro is for EBS, not the i3 local NVMe instances.
Those i3 instances lose your data whenever you stop and start them again (ie migrate to a different host machine), there’s absolutely no reason they would use network.
EBS itself uses a different network than the “normal” internet, if I were to guess it’s a converged Ethernet network optimized for iSCSI. Which is what Nitro optimizes for as well. But it’s not relevant for the local NVMe storage.
The argument could also be resolved by just getting the latency numbers for both cases and compare them, on bare metal it shouldn't be more than a few hundred nanoseconds.
Those i3 instances lose your data whenever you stop and start them again (ie migrate to a different host machine), there’s absolutely no reason they would use network.
EBS itself uses a different network than the “normal” internet, if I were to guess it’s a converged Ethernet network optimized for iSCSI. Which is what Nitro optimizes for as well. But it’s not relevant for the local NVMe storage.