The open-doors effect is significant, though, as is the generally more pleasant face the world presents to the beautiful. It's easier to be nice when the world's nice(r) to you. I think the effects can well outlast the physical beauty, too.
I'm only a sample of one, but since we're sharing stories - my parents were of the "break the child to form the adult" school of thought. Severely abusive, in other words. I believed I was fat, stupid, ugly & boring because that's how I was raised. It was a piece of cake to get my first part-time jobs as a teenager, and something clicked. I realised I was above-averagely attractive and intelligent.
From then onwards - despite a hopelessly dysfunctional relationship with myself - I understood what advantages I had, and used them as best I could. This wasn't very well on the whole but things fell into place for me. My outcomes were not as awful as my choices, because people rescued me unasked. Folks have done me many favours, big and small. This life's done some really shitty things to me (sometimes because of being pretty or bright) but it's done more lovely things.
Obviously I do my best to give back. This means that, if you didn't know my background or my cock-ups, you would reasonably assume I've led an extraordinarily charmed life and wasted some opportunities. Leaving the bad stuff out of the picture - you'd be right.
Now I'm old, overweight, disabled and dirt poor. The world's still pretty kind to me considering. I still give back what I can, and my world's still full of folks being nice. I'm not attractive by any normal standard but I carry the benefits of the last 40+ years with me. It is easy for me to smile at & talk to people, because I've been so very welcome for such a long time. I actually make an effort not to be invisible: I dye my hair weird colours because it's easy & cheap but, if I had more money/energy, I'd be sporting the wildest edge of fashion and enormous jewellery. Averageness has some advantages but, since I learned to swim in a kinder sea, I use what life taught me while I was pretty.
An unattractive woman with ideally loving, supportive, encouraging parents would sail out into the world with more confidence - and she'd definitely fuck up less. But she'd have to work harder for the openness, the nice surprises and the opportunities. Despite her genuine advantage over someone like me, favours would flow less freely around her.
It's swings & roundabouts. But, you know, an 'ugly' person with my background would face a lot more struggles. A beautiful one with an ideal childhood barely knows what struggle looks like. Life is not fair. The most we can hope from the supremely blessed is that they notice the discrepancy and share the good fortune.