FYI, "ribbon cable" refers to a multi-conductor cable made from wires molded into a common (usually corrugated, so it can be cut easily) plastic insulator. What you've got there is FPC (Flexible Printed Circuit), or "flat flex", etc.
Not to say you're wrong by calling it that (it does appear to be cabling, and is in the shape of a ribbon), just what the proper term is.
Indeed, they could've chosen to put quite a lot more on there (including components and active circuitry!), but often this is not needed.
The traces are not "conductive both sides" because the material is constructed much like ordinary PCBs are: a carrier film (made of Kapton, hence the gold color) has copper foil on both sides; is etched, drilled and plated; and sealed with a cover layer (again Kapton, but could be other kinds of solder mask).
Tim