The cable, using a wall charger, usually charges faster than wireless. But "wireless" doesn't wear out or break, microUSB connectors do. You also can't trip over "wireless" and rip the charging connector (and a few other parts) out of the phone, while flinging the phone into a wall.
It's not something you must do, or should do, it's something you can do. Some people love it, some hate it, some don't care. I didn't start using it until there was a standard. Now my daily phone has a Qi receiver in it and I have a Qi charging plate. The plate is on the right side of the desk, the computer and power strip are on the left side. Sometimes I want the phone on my right while it's charging. (I still use the wall charger and cable if the battery is a little low and I'll be going out in an hour - it charges almost twice as fast as wireless - 640mA vs. 1,200 mA.)