That's wall wart, poetic techie for what one of those does to the appearance of a wall.

You can definitely use RG6 for phone lines, because phone signals are really stupid and don't care about much of anything, conductor-wise, except for not being connected to ground anywhere.

It will be difficult to keep it from looking real stupid, though, because you'll need to adapt from the wire style of RG6 to simple two conductors. I'd go with crimp-on RCAs, just to keep anyone from thinking there's RF on the wire, to chassis-mount solder or screw terminal jacks that you take wires off of.

If your email address is in your profile, I'm sending you my reference doc on how to use two pairs for network and one or two pairs for other stuff. That's also completely viable and even looks right if done that way during initial installation, but yes, it won't work with gigabit networks.