They're probably Saudi or Gulf Arab tourists and not Turkish. At least, that was my experience when I have been to Turkey the last time and I'm from the region, I have an easy job identifying people's background from their accent, form and attire than outsiders.
There are some small religious groups that uses a face veiling clothing called "çarşaf". This was also historically used in Ottoman era. this setimes covers below nose, sometimes shows the face. https://en.m.wikipedia.org/wiki/%C3%87ar%C5%9Faf
Usage seems like .01 to 2 percent of women.
I checked the pics on Google Images, they're virtually taken recently with nothing dating back to the Ottoman period to validate this claim. All look like black Arabian abayas and burkas and it's difficult to imagine that çarşafs and abayas are identical like that.
Fun fact, "çarşaf" or more accurately "şarşaf" in Egyptian Arabic means table clothes or bed clothes. It's amazing words and consequently languages evolve and take on meanings over time.
