A more obvious example is minified JS versus regular JS. Briefer? Definitely. More expressive? Definitely not.

I think you're confusing expressiveness of the language with expressiveness of a particular text written in that language. English certainly affords you the opportunity to share more thoughts but given that you seemingly only wanted to express an affirmative, in English 'yes' is pretty much the minimum. You could have said 'Ya' but that is slang. If you open up the choice of language then you could have said 'si', or '#t' or even just '1'. But with such a short intended message, language choice hardly matters.

Certainly if you intended to say more than 'yes' then you failed at adequately expressing the message to begin with so comparisons at that point are moot: i.e., two pieces of text must both express precisely the same ideas before comparisons of them make sense.