Naps are terrible sleep hygiene. Any deviation from a regular set sleep schedule is bad hygiene. Better to get less sleep than to nap and disturb the sleep schedule. Many people develop insomnia this way, especially shift workers.
The siesta is natural and is different from the naps taken from shift workers that are likely either interrupting night time sleep or are shifting their circadian rythm so that their "biological night" is in the day. Same thing for the "biological day" (it will be put at night)
https://en.wikipedia.org/wiki/Siesta?wprov=sfla1
It’s almost like we are not some robots with scheduled downtimes - physiology is much more complicated than to have such a mathematical truths. The only true thing we can conclude is always: this factor might correspond to this effect (and sometimes may even say that it is not only correlation)