The large majority of ovarian cysts are benign and go away on their own. All surgeries have risks. Far too many gynecologists are quick to do surgery since it pays well. And many women's ovary(ies) and/or uteri are removed unnecessarily. So it's encouraging to hear of one suggesting conservative "watch and wait."
If she does end up needing surgery, it's important to preserve the ovary. The loss of even one ovary's hormones has been shown to increase risk of dementia, cognitive impairment and parkinsonism.
I hope this helps!