I never see women with guy friends who are WAY uglier than them. A 7 woman may have 6-8 as the looks barrier, while having 4-6 as the friendship barrier. I've seen this in real life. Hot girls date hot guys and are friends with average guys. Average girls date average guys and are friends with uglier guys. But uglier guys being friends with hot girls are very rare.

Women do have a looks barrier for friends, albeit lower than the fuck/date barrier.