Does it matter if it is a marque or an indie game?
Not to me. If you want voices in your game, pay somebody! I know there are sites where one can look for cheap voice talent.
The voice actor I mentioned runs such a group on Facebook.
Because they can already do this without AI, and from what I hear from game developers making the opponents harder is a huge waste of development time for something most players emphatically do not want. Maybe the math is different with AI, but it is still not something that is in very high demand.
My understanding is game AI is manually tweaked by programmers after a lot of play testing. It is not about making the AI harder to beat. It is about making it better.
So often, as a player, I can spot the AI cheating. It can know things I do not now. It’s a shortcut devs can use to improved the AI player.
I am suggesting they use AI to playtest the game and find a finely honed AI to use in PVE.
You don’t use AI to playtest a game unless AI is going to be your customer.
I would think that AI-assisted QA might be a real game-changer for a lot of software development, if it can be figured out/set up correctly. The ability to generate and test a staggeringly large number of test cases might be a real asset, as would the AI ability to keep track of all of it. And maybe even (speculation here) set it all up such that the AI can tell what code is being run and where the error is, and either fix it or suggest a fix.
But playtesting? I tend to agree with @Atamasama- it’s not going to play like a human, so using it for playtesting wouldn’t work too well I suspect.
As far as the issue of human creators or AI generation, I lean toward the main distinguisher being the size of the studio, and the degree of the voice work needed. If it’s a fighting game of some kind with a handful of combat sound clips of grunts and catch-phrases, then maybe just use AI. But if it’s a dialogue driven game where the voices are a major part, then go human. This is presuming that there’s some extra mojo that a human voice actor brings to the table for that more intensive work vs. “Ow!” “Ugh!” “Yaaah!” etc…