This can have a lot of uses. Courts can know if a defendant is guilty or innocent immediately in almost all cases. Businesses can know if their suppliers and employees are capable. Employees can know if the employer will actually give them the raise that they have been promising. We may all be able to know if our dear politicians are lying.
This will improve our lives and it seems like a marketable product. Why hasn't anyone made it so far.
If your use cases cases as described in the OP are for real rather than satirical, you are a naive person and should spend more time reading about the history of technology to understand how and why good intentions can have catastrophic outcomes.
Skip to the end for the tl;dr:
The foundational premise of AI lie detection is that lies are there to be seen with the right tools. Psychologists still don’t know how valid that claim is [...]. The promise of a window into the inner lives of others is too tempting to pass up, even if nobody can be sure how clear that window is.
“It’s the promise of mind-reading,” says Wilde. “You can see that it’s bogus, but that’s what they’re selling.”