> Of course this is just a toy example. But suppose you had a different task that is I/O bound, like processing terabytes of jsonlines files.

If this task was the bottleneck in a large scale system then it would definitely get hand optimized after a proper analysis.

But if this is an occasionally run task or something otherwise not business critical that doesn’t bottleneck anything, spending orders of magnitude more time hyper-optimizing it would be a waste of time and money.

Match the solution to the job. Optimizing everything is one of the age-old mistakes in computer science.