Dielectric grease is a silicone based insulator, it is non conductive, moisture resistant and non hardening. It was first used in in the automotive field when electronic ignition systems were introduced into the automotive industry. It was used on the terminals of distributor caps, rotors and spark plugs to reduce Radio Frequency Interference in AM radios. It was found to very useful for other related purposes as well. Because of these characteristics it is very useful in preventing many undesirable problems we face. There is a right and wrong place to use it.
For Secondary ignition (high voltage side)component's it excels. It prevents moisture intrusion anywhere it is utilized such as coil towers and plug wire connections, it will increase plug wire life by keeping the wires from drying out and cracking over time, it keeps the boots soft and from sticking in place avoiding damage to the wires during routine service. It should always be used when service is being performed on the secondary component's. No such thing as to much, just no need to waste it either.
It does not improve a electrical connection, It does prevent degradation of the connections.
It also can stop what we call cross talk in very sensitive low voltage/low amperage circuits such as computer and sensor connectors when use properly. Cross talk is when a very small amount of current flow bridges a insulated area to another sensor signal circuits and changes that value sent to the computer. It only takes a few milliamps for this to occur and usually only happens when the surrounded area is contaminated with something, it does not take much and in many cases is not visible to the naked eye. Keep in mind it does not improve the connection though.
Stabilent 22 is designed to improve and protect electrical connections of this type for low amp sensor circuits and is a far better choice for computer connectors (meaning the metal to metal contact portion). Dielectric grease for the insulator part of the connector to prevent contaminant intrusion.
Nothing is a substitute for poor pin fit though
Hope this help clarifies where and how to use these two items