Freezer paper and parchment paper are two different things. Freezer paper is a thick paper with one side coated in wax. Freezer paper has a very specific purpose, which is to wrap meat that's to be frozen. The wax coating helps preserve the quality of the meat, and the unwaxed side can be written on for easy identification. It’s also popular for wrapping seafood and cheese because the wax coating lends a degree of water resistance to the paper. Freezer paper is unsuitable for cooking because the wax surface will melt when exposed to heat, and the unwaxed side can catch fire.
Parchment paper, meanwhile, is coated on both sides with silicone which makes it both heat-resistant and freezer friendly.