Does it work with a smart TV or streaming stick?

It pairs over Bluetooth with Windows, Android and Chrome OS, so it suits Android TV boxes and tablets. Check that your TV or stick accepts Bluetooth keyboards before buying.

Is a USB receiver included?

The listing describes Bluetooth connectivity only and does not mention a USB dongle. Plan on pairing it directly with your device's Bluetooth.

Is the touchpad good enough to replace a mouse?

It handles basic pointing, scrolling and clicking for couch browsing. For precise work like photo editing, a real mouse is better.

What layout and language is it?

It has a standard QWERTY layout in English. There is no mention of other language versions.

Is it worth it over a separate keyboard and mouse?

If you want one small device for a TV or tablet, yes. If you type for hours, a full-size keyboard and mouse will be more comfortable.

Can it switch between several devices?

The listing advertises multi-device support across Windows, Android and Chrome OS. It does not state how many devices can be paired at once or how switching works.