It's a public space. You have no expectation of privacy. It's the same reason license plate scanners are a thing.

It's the automated equivalent of eyes.

Everyone seems concerned about what it could be doing, not what it is doing.

I could sit next to a vending machine and make notes on the gender and sex of each patron for demographic purposes, nothing would be illegal.

Why? Well, that's easy, I want to stock my vending machine in order to make money. Instead of testing different layouts which would take a lot of time, I could predict how well certain stock would do based on preexisting market research.

This appears to be just that, but with a camera.

Now, you can argue "but it could be worse"! That's not a valid argument. It could always be worse for things you don't know about. If it holds up to be true, as stated, it's just what it is.