I started my electrical apprenticeship in 1960 working in a large Railway workshop. I was extremely fortunate to work with very experienced journeymen from a wide range of trades. I often worked on battery banks, single cells strapped together to form high Voltage batteries, you had to have your wits about you as these had the capacity to do some serious harm. I also worked on overhead cranes with drum controllers for varying the speed of the hoist and travel motors, these had hundreds of large copper contacts that would wear rapidly if not lubricated.
Fast forward a few years and I was working construction at a major pulp mill expansion and I was told to put a switchgear battery together, from memory this battery was about 100 Volts DC used for opening and closing the main circuit breakers. I got called into the office one day to see the bosses and several of the clients Electrical Engineers standing around, I thought to myself I'm in trouble now, but no they just wanted to find out why the battery I had put together was pristine while several in other switch-rooms were a mess of corrosion. The difference was I had applied a little petroleum jelly as I had been taught as an apprentice.
If you put the leads on a battery without some form of grease it forms an electrical cell Lead to Copper, the moisture from the atmosphere acting as the electrolyte. Also the Oxygen in the air reacts with the lead to form lead oxide which is an insulator. You can demonstrate the insulation effect of lead oxide (a darker grey layer), take the probes from your Voltmeter and rest them lightly on the lead battery posts, chances are it will read zero Volts.
I'm guessing 95% of new motorcycle batteries go together dry, but this is not a good idea as Bonaventure found out and showed in his pictures, he caught it early on before anything serious happened.
An electrical contact is not two perfectly smooth surfaces touching, if you look at a microscopic view it's more like a couple of mountain ranges.
Often the lead oxide will creep in between the metal components and completely disconnect the battery.
I'm sure you have all experienced sudden loss of power with a vehicle battery, usually happens in the middle of winter when the heavy start current fuses the last little bit of metal still making contact, a few cents worth of Vaseline will prevent this.
Don't use anything rather than Vaseline, I'm not saying other forms of grease aren't better just that Vaseline is perfectly adequate. According to others Silicone dielectric grease does more harm than good.
In conclusion if you would rather follow some ill informed advice rather than my 50+ years of experience go right ahead.