Is not in principle.
Wireless networking has come a long way. The chances are that a decent modern wireless network outstrips your Internet speed, so for most applications it works just fine. But with online gaming, streaming video and audio, and more happening over that network, wired still offers better speed and a more reliable connection. Even on your local network, you may be streaming from a media server or backing up to a central location, so a good connection matters even more.