It's a pointless discussion, as I could argue that every aspect of human expression is indeed art, whatever that means anyway. The term "art" is so vague that it hardly means anything anymore, that is why people tend to argue about what is art and what is not, because the term is not clear to begin with.
But suppose we all agree that video games are indeed art, what do we gain from that? Nothing.
What do we gain from agreeing they are not art? Nothing.