Simple blankets are the ones that aren't Fireproof or Waterproof, and thus currently only serve as a letdown when you get one.

With the proposed feature, whenever it is determined that an acid or lightning attack would cause item destruction, the simple blankets are destroyed first. Since different people are on different sides of the issue of creating new blankets for specific acid protection or specific lightning protection, it would be nice in the meantime to use those useless simple blankets as a way to prevent instant destruction of items when hit by acid or shock... at least until you run out of simple blankets that is.