What's it Good for?
No Wires! - WiFi has the benefit of not tying you down with any cables. you're free to roam and use the Internet anywhere!
Convenience - With a simple one time setup once WiFi is setup, it doesn't need to be setup or "plugged in " again.
More Devices - It's not exactly possible to wire in a mobile phone or a thin and light laptop. That's where WiFi comes in!
What's it Not Good for
Interference - WiFi uses radio waves to communicate to and from your devices like most technology. Unfortunately that means your WiFi may struggle to always stay loud enough to get you a constant connection!
Slowing Down - Walls, ceilings, furniture and distance. Anything can interfere with a WiFi connection, this is why your speed may vary from time to time.