With games it's kind of unavoidable in a long run, they are interactive and dynamic, be it outright mods or just new situations arriving out of gameplay. Being able to adopt the voice or automatically or generate variations of a sentences would be a huge benefit. Not exactly a new idea, we had things like iMUSE that dynamically adjust music for 30 years and effects like reverb have been dynamically added for at least 20. Most cutscenes are also realtime rendered for exactly this reason, you can't reflect a costume change in a static FMV sequences. Now imagine you want a character to make a comment on the costume or weapon you are currently wearing, you'll quickly end up with a combinatorial explosion of the amount of stuff you'd have to record.

Expanding it all with AI voices or AI filtered voices (think RPG with character creator) is just unavoidable. You can't drive a dynamic medium with static content to it's fullest potential. And of course many smaller indie games just don't have the money for full voice over to begin with.

I also wouldn't mind AI just as filter to change a voice, since some voice actors are just way to recognizable.