Although the Fresnel shader can be used in any material channel (preferred is the Reflection channel), it does not affect the bump or displacement channels unless used as a secondary channel within Fusion or something similar.

Left a Fresnel shader in the Color Channel. Right a Fresnel shader in the Transparency Channel.

It's hard to imagine not using a Fresnel shader when rendering glass. This shader can also make numerous types of materials look more realistic. Because the greater the angle at which you view a surface, the more reflective any surface becomes.