[tscs37]

>The argument is that the formalism of Big-O notation itself is generally irrelevant (except where it isn't, obviously).

That sentence kinda defeats the argument itself. If it's irrelevant except where it is not, then your argument is obviously true.

We could also say that some number X is always not 1 except when it is.

>You don't need CS101 to understand that a nested for-loop probably scales worse than a single if-statement.

That is true, but it's just Big-O applied via intuition rather than learning.

Big-O is mostly the expression of intuition for some people.