The burqa, and niqab are ugly enough:
|Afghan Blue Burqa|
But the burghu looks like a cross between something out of some fetishist/S and M catalogue and some kind of muzzle you'd use on a vicious pet. It also disturbingly resembles a mustache, at least in the photos below, which are published in Mutwalli's book.
Mutwalli actually has an uber cool website, and a Pinterest board where you can see other photos of traditional outfits worn during the period of time she writes about, some of which are actually quite beautiful. But this burghu... it's just another symbol of the "muzzling" of Arab Muslim womenfolk. According to some info on one of the photos on her Pinterest board (although that one is called a Bandari costume), the younger generation no longer wears them, and it's usually married older women and rural dwellers in the UAE, Oman, Qatar and Arabs of southern Iran and southeastern Turkey who still do.
Source: Gulf News