It's not extra, you'd be replacing the existing window you already look out of.

Either way, windows are not generally the focal point of the room, you'd have an awkward viewing position.

Most likely the sun would be an issue too, the TV picture would only really be visible during dusk/dawn/night.

Also do you have shutters behind the window so outsiders don't see your screen or...?

I don't see any sort of practicality.

I can see this working in a glass house, which aren't that uncommon...some new buildings really go on maximizing window space on a skyscraper so that you don't really have a wall on the exterior (more common in China than the USA for sure). See for example:

https://www.luxurychicagoapartments.com/blog/luxury-design-e...

If you could turn the window dark with an exterior black out shade, you could have a TV on-demand without completely ruining your view.

It is a very niche use case though, but one I've thought of before when looking at some newer luxury housing that goes for big windows on all sides.