I'm currently wondering a bit about vehicle and bigger weapons in D6. Aside from a few examples in open space d6 and star wars I've seen only examples where vehicle weapons have ever growing amounts of dice but still count as size 0 weapons.
Thus there I began to wonder if there is any reason for that.
If we take a side winder for example I've seen it as 12D6, but thought there why not only 3-4d6 and an appropriate size of 9+. Similar for example for a nuclear blast or an antimatter blast. Also similarily for a bazooka. Even though it is held by humans it is made to fight vehicles.
So am I overlooking here something? Thus is there any special reason I've overseen so far for why this most D6 derivates do use more and more D6 for combating higher size beings/vehicles instead of just adding "size" to the weapon/weapons effect ?
To make it a bit more clear I'm looking mainly there ruleswise if there is any explanation to there (designwise it could be to reduce confusion among players,... that is clear although also confusing because it means up to 20 dices to be rolled, but maybe I'm overlooking here something rules wise or if not designwise)