Rigid flex PCBs present several mechanical benefits over standard ribbon wires in various use cases, and in some instances, they display better chemistry. As mentioned earlier, a flex PCB can be produced in complex 3-D shapes with branches to various connectors, which is impossible to create with ribbon wires. Furthermore, these boards can be interfaced with their rigid counterparts without the comparatively tall and massive connectors flat cables need. For rigid-flex designs, they are more integral with the PCBs and get rid of external connectors completely. Still, the conductor density of flexible PCBs is better than that of ribbon cables. 

There are some exclusive benefits of flexible PCBs versus conventional ribbon cables apart from their significant differences. For instance, Kapton (one of the common flex PCB materials) has exceedingly low outgassing in ultra-high vacuum conditions. While Kapton-insulated ribbon cables are available in the market, they have few conductors and cannot be routed in tight angles. 

Ribbon wires insulated with Teflon and other plastic substrates outgas fluorine and other reactive compounds when exposed to high vacuums, which attack electronics in closed containers when significant measures are not put in place to release the gases fully.