Ancor's double crimp connectors have an extra long barrel with two crimping sections.
The interior section is thicker walled and narrow for crimping on the wire's conductor (in the traditional fashion).
The outer section of the barrel is thinner walled and wider, and is crimped over the wire's insulation for additional mechanical strength.
This provides strain relief, and makes the connection less likely to fail if the wire is pulled.

Premium nylon insulation wont split or crack like the opaque/solid color PVC insulation used on automotive connectors.

Insulation resists water, oil, chemicals, acids and UV degradation
Barrel is tinned to provide greater corrosion resistance
Seamless barrel construction prevents barrel from splitting