HDMI is a connection that has become the norm for digital setups. It's most often used to connect a video source, like a computer, laptop, or game console, to a display device, such as a monitor, TV, ...
Unless you have the technical know-how, setting up devices like home computers and other electronics like a TV with a LAN port can be daunting. You might get stuck searching for YouTube videos that ...
Some (many?) HDMI cables can also carry Ethernet over HDMI. The main use seems to be to provide internet connection to a smart TV from a cable modem box. Currently I have an ethernet-USB adaptor ...