While travelling, I met a Japanese guy who answered just like that - "Tea or coffee?" - "Yes". To him, it seemed to be natural. Either that's his personal way of thinking, the Japanese culture, or his understanding of this kind of questions in a foreign language (English). Everybody who met the guy for the first time was quite surprised by his answers, and he didn't understand why.
Back on topic: as 'but' seems to have so many different meanings, I doubt its introduction would make the language Perl clearer in any way. For me as a German speaker, I first think of 'but' indicating some sort of contradiction or distinction. 'But' in the sense of 'and' is also quite common, but that would make no difference to the existing operator 'and'. So I still don't really dig the possible benefits of a 'but' operator, and I'd most probably never use it.