My old Epson 3800 was always connected via USB (about six feet from my router). When it died and I upgraded to a P800, I expected to use the same USB cable. But because WiFi was possible, I decided to try the P800 on WiFi first, and I've been running it that way for over six months with no problems whatsoever.
In fact, the reason I haven't responded to this thread sooner is that I had forgotten that the new printer was on WiFi instead of USB.
I suggest that you try it. The setup is easy, and it will be easy to switch to USB if you ever find a reason to do so.
-Eric