It's easy to find yourself with more sources for your TV than it has inputs. Most TVs just have three or four HDMI ...
If you have a PlayStation, an Xbox, a Switch, a cable/satellite box, or a media streamer and an ARC-supported soundbar, that's easily too many sources for the meager number of HDMI inputs found on ...
My cheap-ish Samsung (cheap for a QHD) has an HDMI and a DisplayPort input. If I hook up a laptop to each input, both laptops think the screen is on- even the one who is not currently being displayed.