It's for the initial cranking. When you tear down an engine, all oil galleries and oil pump are empty of oil. For the priming, you gotta crank the engine with ignition coils and injectors unplugged to make sure to have oil everywhere in your engine. Then you replug everything, start your engine and check for leaks or unusual noises.
The good thing about jelly is it's gonna suck the oil from the pan as soon as you'll crank. And also the pump will not run dry for a second.
Thanks for answering for me!
