Finding backgrounds for indoor portraiture can be a pain after a while. You can get mileage out of proper backdrops and different lighting setups, but there's an option for punchy portraits with for all intents and purposes, unlimited variations.
For years I have been using my Samsung tablet as a backdrop for commercial macro images. It has been a staple of how I work for a while and I've used it in a number of ways. For some reason, however, I've not once made the connection of using a television for bigger subjects. In this video Joe Edelman, the happiest photography educator I've ever seen, goes through some shots he's created using an LED television as a backdrop and they are stunning.
There are a few caveats to this method I would say: firstly, you need a large LED TV which if you don't already have one, is quite the expense (albeit one that has other justifications to go along with it.) Secondly, you need to know how to light properly to avoid an odd, mismatched portrait. Creating cohesion between the brightness of the background and the foreground is paramount to success. With a bit of trial and error, however, you have access to so many creative images you will essentially never run out.
Isn't green screen/blue screen old but easy and cheep way to do unlimited backgrounds?
in theory yes, but at the same time it can be quite hard to make it look good and not like some weird photoshop mishap. You also have to be quite cautious with the subject. If that has green or blues in it, obviously things can get tricky.
It's probably easier to create depth with a physical background and to make the subject more part of the scene. In the example the photographer also uses blue and pink gels light the subject and to match the colours of the background he is using on the tv, which really places the subject in the scene and makes the model part of it.
If you want to light up your subject with coloured gels with a green screen behind it, the gels might also "mess up" the colour of the green and make keying out harder. You can of course not use gels, use a green screen and try to photoshop fake gel colours and such in after, but again. To make it look natural and good can get tricky.
Using the TV-method makes it all happen in camera, which will make post processing a lot easier.