Why do I need to use a Ferrule?

I am glad you asked! I have 8 great reasons why:

Reliable electrical connections -- all wire strands conduct current.
No spreading of wire strands after a wire is clamped into a terminal block or other component.
No fraying of wire strands, particularly in cases where the wire is very small or is removed often from its housing for testing purposes.
No breaking of wire strands in cases of bending, wire stress or vibration.
No unwanted contacts. Ferrules eliminate the possibility that strands might accidentally touch another termination and create shorts.
Easy wire insertion in a terminal block clamp, particularly for smaller gauge wires (28 through 18AWG).
Permanent crimping of two or more wires (jumper connection) before insertion in the wire clamp (twin wire ferrules).
PLC's - Ideal for terminating wires in close proximity to each other. Eliminate possibility of glitches