programming

Okay, so I've been messing around with Lua for the past week and looking at the different Npc files that control their behavior with an Lua editor. Now I can basically alter what the TG merchant says in his text dialogs, what he sells, and the prices he charges, but just looking at the code can...

Could somebody please explain in layman's terms why (or even if) it is preferable to have a block ID for every new block variation, as opposed to having one field determining shape (cube, wedge, slab1234, ...), one field for the material (hull, armour, glass, light, rock etc.), and a third field...