Perhaps not “incompatible”, but clear fit, since the rest of the sutta does not talk about benefit. On second thoughts, you are right that there’s no harm adding the meaning of “benefit” to it as well.
Similarly to a query on the tilakkhana forum, I find it not intuitive how we can pack so many distinct meanings into one word (attā): those entities are not to be taken as yours (1) because they provide no value/benefit (2). It seems like more of an either/ or thing. But this is only my intuitive sense of languages! I am also well versed in another language (chinese) and I found it hard to find a word that contains 2 distinct meanings together, not either or (eg 1 and 2 instead of 1 or 2). Normally you can translate a word with few characters/ words of another language, but they both usually just carry one meaning. eg for chinese, to say both “not yours” and “not to your benefit” I have to use 2 separate phrases “不属于你 (bù shǔyú nǐ) and 对你没有好处 (duì nǐ méiyǒu hǎochù). Because they are 2 distinct set of meanings! It is possible that one word has 2 meanings and used either/or (like a pun), but rarely are 2 meanings stacked on each other.
Of course Pali could work differently and there could be multiple meanings stacked on top of each other.