It does make a difference, if you are in an environment not well lit, having a keyboard lit is easier for typing.
You can also buy a light, who will be plugged in the USB port. But for a general usage of a laptop, you don't need it.
On the site of Lenovo, they wrote "The Backlit Keyboard is an Optional / Customized to Order feature",
many people complain they don't have this kind of keyboard.
You could have a connector for the light, but you will need to open the laptop to figure out if it's there.