At least in stats, the use of greek letters is helpful. Usually, the upper cases are kept for function like T(x) or to denote random variables. The lower cases for observed values. So when we see a greek letter, we know right away it's constant or a parameter.

I agree completely, and would emphasise 'at least', or change it to 'for example' even.

I only meant that criticising anyone for using them in the first place is unfair/hypocritical, because we'd quite readily do the same with the Latin alphabet.

Not everyone speaks English. It's nice to keep that in mind when naming things in the universal language that is maths. S, T, N might make sense in some languages but not others. More greek would at least level the playing field or something.

I didn't for a second mean that they should be used instead of Greek; just that 'we do it too, so don't be surprised that somebody else abbreviated things with their script'.