Organized religion is essentially culture, and Islam is 7th century Arabic culture. Back in the day and in that area (desert), dressing up a certain way might be beneficial.
I have mentioned this before, but once I saw a full burqa woman at the Sentosa beach. It was in the afternoon and the sun was very hot. Her husband and kids were in their swimwear. I felt uncomfortable just by looking at her. We NS slaves know all about getting heatstroke.