Speaking from a position of spark plug ignorance...……..
All I can suggest with the four post plugs, is that obviously the spark can only jump to one? (Is this obvious?), so I'm thinking that it will take the shortest route until that erodes, when it will then take the next electrode with the shortest route. So arguably extending life considerably?
My Roadster plugs have single electrodes with a pointy end (technical term). At around 20k miles they were immaculate, so I put them back in.
