Well, you're right. But somehow, my mind had wired "adult" to this kind of definition (wikipedia) : "Biologically, an adult is a human being or other organism that has reached sexual maturity". And therefore, I associated that to "organism" (I didn't think about animals, but I'd venture to say that when compared to computers, many familiar animals like a dog are more intelligent, but that's a debate, I understand that).

So in this sense, I found it surprising to associate a word that I use for "living"/biological things to a digital thing; specially in the context of A.I.

Maybe the term adult is, for me at least, very loaded with lots of meanings that go far behind the simple notion of "maturity"