Using a sealant such as AIO on your windscreen works much like a silicon film, such as RAIN-X. However, when I was a dumb kid (as opposed to the dumb 38-year-old I am now) -maybe about 13- I waxed the old man's 71 Olds Cutlass, and I included a nice carnuba coating on the front glass. Believe me, Pops wasn't pleased, and I DON'T recommend you do the same.
Maybe things have changed, but in my experience, "wax" on the windshield is a great way to nix the effect of windshield wipers! Stick with dedicated products; clear vision in the rain equals safety!