Think of your home network like a highway. A wired network is just like a multilane highway. Each car has it’s own lane and can travel at any speed without impacting others. But a wireless system is like a two lane highway, unless you have a router that supports both 2.4GHz and 5GHz (giving you two more lanes). While having the second band does give you two additional lanes, there is still the matter of traffic and interference.
Even the best router cannot ensure adequate Wi-Fi coverage. So, in many homes it helps to add access points. But, you need to be mindful of Wi-Fi limitations. That’s because the more devices you add to your wireless network, the more bandwidth you will use. To help lighten the load of your wireless network and enable it to function more reliably, you need some of your connections to be wired. And, the only way to do this right, is by using networking switches.