Lightning storms can do quite a lot of damage to electronics. When lightning strikes on or near the electrical grid, there is a risk of all that current travelling through the powerlines straight into your computer or tv. When that happens, you will most likely end up with a useless pile of electronics, unless you have a functioning surge protector which you plug your devices into.
Surge protectors are fairly inexpensive, and some of them even come with a warranty for the devices plugged into it. Your surge protector needs to be plugged into a properly grounded wall receptacle for it to function correctly. It is also important to remember that it will only work for a few surges. There should be an indicator light letting you know if there is a problem with the surge protector. It will still work as a power strip, but you shouldn’t rely on it for protection.