For what it's worth, when crimping an end on a wire cable it is important to have the insulation up flush with the end being crimped to the cable. Nor should the wire extend out through the crimping sleeve. (where the crimping is done)
If you can see the copper wire showing it can lead to problems later. Those installations are known as "shiners".
These cable ends are properly installed.
Problems like this occur when wire is exposed on either end of a crimp.
Purpose made tools are designed to solve problems. Unfortunately they can’t solve the problem that is caused by trying to avoid spending money to create just a couple of crimps!