Yes, wired is more secure from many standpoints. First of all, as the person above me points out, you need to gain physical access to the wire in order to attempt to snoop it and have specialized tools to do so. Above and beyond that, breaking through the siding of someone's house, tearing out their insulation is something that is illegal and it would be difficult not to make the occupants aware of that due to the racket it would cause. Of course, there is always the possibility that such a criminal would be willing to wait for an opportunity for the occupants to vacate the premises in order to perform this act. Even so, the occupants would probably be aware of the illegal activity due to the physical damage caused.
With a wireless network on the other hand, the hacker doesn't have to be on the other person's property to sniff their network and can do so without the person being aware of it. Furthermore, if the person never once logs on to the other person's network in anyway so as to log packets that indicate such a thing and instead just snooped the over the air signal and captured personal information like a credit card number, it would be hard to prove that they even did such a thing. Not that I condone such actions but to me snooping a wireless signal is like overhearing a loud conversation in the next door neighbor's house.
For these and many other reasons, when our house was built, I worked out a deal with the guy overseeing the construction of our house and ran my own cable and put my own junction boxes and patch panel in.
"Hey Ivan, check your six." -- Sidewinder missile jacket patch, showing a Sidewinder driving up the tail of a Russian Su-27