Most Scots would say "We are fine" . Only the young say "we are good" particularly social media users
I think you've misunderstood the translation.
'We are fine' > Tha sinn gu math
'We are good at football' > Tha sinn math air ball-coise
'Good' in this context refers to ability or the like i.e. being 'good' at something.
It would be nice if that were explained somewhere, because the English translation is ambiguous.
How does being good relate to clothes?
Think of the category names as loose guides. Sentences are chosen to equip learners with the grammar they need. I doubt it does any harm!