Exactly, that's not a flaw, that's rational behaviour. Why design an intricate solution for a one-off. Using 15 times the amount of time it would have taken you manually to automate a pretty standard task is just stupid, though we all do it.
Do the first thing that works, don't overthink it.
I think the flaw is you misinterpreting the argument.
In my opinion, the bottom line with obvious caveats is this - Human-time is more valuable than CPU-time.
If you are shipping at scale then the calculus is different - Don't waste end-users' human-time and their cpu-time and/or server's cpu-time.
If you're writing code with a team the calculus is different - Use/Learn techniques and tools to reduce the teams' human-time wastage plus all the above.
If you're writing code just for yourself the calculus is different - Save your own human-time.
