[SuperGent]

Also, it is a way to get A-list celebs involved and cash in on their popularity.

[pcroh]

Maybe someday we will see (or hear) Siri's voice star in one of those Disney flicks.

[minxomat]

Weird example since Siri is based on one real woman's voice. Maybe one of the WaveNet "personalities" might be a better example.

[have_faith]

Or the Japanese voice idols?

[Filligree]

Vocaloids?

Those are deliberately made to sound unnatural. Not to say it changes anything, and they've already shown up once or twice in anime.

(Though the only example I can name off the bat is Black Rock Shooter, and that doesn't include the voice. It's complicated. Mato is complicated, too.)