are those bike cables or for towing cars?

Towing Shimano hybrids! :)

I have a bike with braze-on cable guides and I'm running 11-speed so I want/need least possible cable friction. But I'm questioning the wisdom of using some cable liner at just these sections. Seems like a recipe for trapping water and grit? Whereas you can keep just applying grease as needed? My cable guides seem fairly smooth.

I was considering either the Nokon liner: Amazon.com : Jagwire L3 Liner Kit for Nokon Systems (2000mm) : Sports Outdoors : Sports & Outdoors

Or just housing liner: http://www.amazon.com/gp/product/B00...A2TE9IQP68MWQU

But without a way to seal the tube from accumulating crap, it seems like a bad idea?? FWIW, the Campagnolo cable ends actually have rubber seals. I have no idea how to create a robust rubber seal for a little piece of tubing around the cable guide area.

http://i1382.photobucket.com/albums/...ps1bhlu1wd.jpg

If a tubing noodle is used under the bottom bracket, it should have a window cut into the bottom at the lowest point, to allow water to drain.

I've worked on a couple of frames with disturbing sharp steps that the cable dragged over, and found thick-walled poly tubing that fit tightly into the guide loop that the cable routes through, such that a minimal length of the tubing could be positioned so as to cross the sharp step feature just behind the loop.

For the standard guides as on the OP's frame, I would run it bare, but would experiment with lubricants while the powdercoat wears down, the thickness of which might be reducing the inside radius of the guide slot, creating a wedging/pinching action on the cable.
GripShift grease is the slipperiest (by far) lube that I've ever used for cables sliding against polymer surfaces.