It has voice control and some sort of remote camera features you access through the app. I guess it makes sense for instance when on a vacation, you can inspect the house this way.

• The questions virtually nobody that owns these asks.

I weep for our race.

Why does anyone need a robot vacuum cleaner? Nobody does. You can use a normal vacuum cleaner. Or you can have a dirty house. So "why does it need..." is automatically the wrong way of framing it.

So, why do they have:

1. a camera? To use computer vision to try and avoid socks you left on the floor.
2. internet access? Because the cheapest way for a company to let a large market control a device nowadays is through a smartphone app. That means it needs to be network-enabled, so internet-enabled is no extra cost. It brings some benefits, too; it means you can control the device (whatever it is) when you're out. If you forgot to set the robot vacuum off before you left the house, you could do it while out.
3. a microphone? These are rare, but given that you already have a device that can trundle round the house, is internet-connected, and has a camera in it, why not add a microphone so you can use it as a security camera?

Nobody needs any of these features, but each provides something useful to someone.