This is an unfortunate reality in most aspects of life. Physical attractiveness _does_ matter, and has many advantages. Whether in job interviews, relationships (non-romantic ones too!), performance assessments or even the judiciary system: attractive people are seen more favorably.
Honestly, I almost wish they would stop releasing these studies, it's like "I get it, if you're ugly, not only is it harder to get a date, but you'll get paid less, be less likely to get promoted, get rated as less productive/smart/etc., and if you get caught doing a crime you'll get a much longer jail sentence."
Ask any girl and they will say that people who wants to be friends with them greatly depends on the current attractiveness of her. I think it is less true for males, but nonetheless I feel like there is correlation.
I still think the effect of attractiveness on female-female friendship is much much more than male-male friendship. I don't know if there is some known theory or reason for it, but you can see in a group of female friends, the attractiveness level is in similar range more often than not(of course speaking from anecdotes, nothing to prove).
I would love to see a double blind study on attractiveness and job interviews, but this would be pretty hard to do (facial prosthetics?)
Response rate of identical resumes with different portrait photos attached would be interesting.
I recall seeing an experiment shown on a news program with 2 different teachers in a young (like 1st grade or so) class. One of the teachers (they were actually both actors) was conventionally very attractive, the other very plain (I always thought "How's that for an acting job: yay, I got the role of ugly teacher.")
The thing is, with kids that young, they were very transparent about their feelings toward the attractive teacher "She's so pretty! She's so nice! I really liked her." It was classic halo effect stuff.