Cereal Bags

Factual Questions
1

I noticed that on Kellogs Smacks cereal the bag that the cereal is kept in is a silvery wax paper. Whay is this used as opposed to the regular translucent plastic bag?

2

The Straight Dope Science Advisory Board already tackled this one—

http://www.straightdope.com/mailbag/mfoilbag.html