It really doesnt have to be perfect to trick someone. You're expecting this site to be fake so you're listening carefully. If you weren't expecting anything and you were in the middle of a busy day at work, you are much much less likely to notice any discripencies.

We already have stories like https://www.forbes.com/sites/jessedamiani/2019/09/03/a-voice...

That said, as far as harms go, i dont think this is all that bad that it should preclude creative uses of this technology.