Why does Audio doorbell need batteries when it's wired?

[Xmantium]

I just bought the Arlo audio doorbell thinking I've got a wired doorbell system and don't have to worry about batteries inside the doorbell.

To my surprise it needs batteries and won't power even though it's wired.

Why does it need batteries when it's getting enough juice from the wired connection? Other Doorbell don't need batteries when it's wired.

[jguerdat]

Just the way it was designed. The video doorbells don't work the same.