These threads always turn into something else other than the actual question!
The OP didn't ask why women chose not to take HRT
She asked what were the benefits of NOT taking it.
(That's something very different.)
You can't prove a negative!
The discussion about it being 'natural' has been blown out of the water years ago. Because all the world-renowned menopause gynaecologists agree that being without estrogen for 1/3rd of your life is a risk. (This has been written about at length in the International Menopause Society journal, Climactic)
And they do compare this extra 1/3rd of life now to shorter lives of women in previous generations. Many women will live to 90 which could be 40 years without estrogen.
50% of women over 50 will get /have osteoporosis. That's a fact. And it's down to loss of estrogen. I've been involved in talking to women with severe osteoporosis through my work and it's a very underestimated disease. It's painful, disabling and causes more loss of independence and deaths in old age than female cancers.
HRT is licensed for the prevention and treatment of osteo in women (under 60 at least).
So- sorry this is so lengthy- IF you are not using HRT or stop at a young age, your bone health should be part of the decision-making. The NHS doesn't offer screening for bones as routine until you have had a fracture (typical- deal with things too late) but you can have it done privately.