That's correct. With many concurrent connections, you save memory (from thread stacks) and context swiches (since you don't need to switch thread to process each socket).
If all you want is a single request (and you have wait for results to continue work), you don't gain anything by going async.
> If all you want is a single request (and you have wait for results to continue work), you don't gain anything by going async
This is true for HTTP version < 2 because of the head-of-line blocking. With HTTP 2 I think a single connection will see a better throughput if not massive increase.
If all you want is a single request (and you have wait for results to continue work), you don't gain anything by going async.