But the basics are pretty much the same, no matter if it is python or assembly: does this one-liner run entirely or mostly in L1 cache, or does it have to wait

But the basics are pretty much the same, no matter if it is python or assembly: does this one-liner run entirely or mostly in L1 cache, or does it have to wait for RAM access repeatedly? Does it have to wait for disk or does it have to wait for network? Repeatedly? People who fail at this won't be able to understand the difference between situations where python or not doesn't matter much and those where it does. Understanding that "computers are fast" (even in python!) is a very important step towards understanding where we make them slow and whether that is because of waste or because the task is naturally expensive. Based on your skepticism i assume that you just haven't had much exposure to people who are really bad at these thing, despite having all the formal education (and the paycheck to match). "I'm working in ${absurdly high level language}, of course i'm not supposed to care for performance" is what they tell you before venturing off to make a perfectly avoidable performance blunder that would be crippling even in fully vectorized assembly, followed by a few days spent transforming all their code a different, but perfectly equivalent syntactic representation that looks a bit faster.