It is interesting that they've done this reasonably successfully, impressive technology. Novel ideas can have inherent value, absent direct uses they may have, as they can be a stepping stone toward other inventions. But, I'm having a hard time coming up with a use case that isn't predatory or intentionally misleading. Company support agents pretending to be human, for instance. Or, taking the next step on AI girlfriend/boyfriend type interactions. Or, outright scams. Models already do an excellent job with voice cloning, at least for intonation and timbre, adding realistic conversational tics makes it even more likely grandma is going to fall for it when her "nephew" calls needing help.
But, that seems to be extremely common with new tech these days. There's always an angle that is unsavory. Marketing, scams, propaganda, surveillance, killing, that's where the money is, so everything bends toward them.
Especially when you keep in mind that not everyone knows english as their first language. I know he's a bit controversial sometimes but Neil deGrasse Tyson is easy to understand and explained interesting topics in his podcast (I could still understand most of it when I was still getting used to listening to english 15+ years ago).
If conversation is the new interface then we will need UX designers to take care of this.