If sunscreen within products isn't protective enough, why is it added? [Sun Care]

Beauty Tips For Body Care
I'm curious why makeup and skincare brands include sunscreen ingredients in their formulations if the skincare community is in agreement that these formulations don't provide effective Sun protection? Is it a marketing gimmick? Do they assume many buyers don't or won't apply separate sunscreen?
Girls Blog 2015
Submitted by fallingleaves789