I'd trust the world champion of chess to not mention physicality as a possible reason unless it had merit. She's been playing chess her whole life.

I'm not disagreeing with her opinion or negating her experiences, it's not my place. That said, classical (3h+) isn't the only form of chess, and it could be something that is personal to her and not representative of female players as a monolith.

Logically speaking, it's still a disadvantage even if it's one that matters less in some scenarios. Gender is highly predictive of a lot of biological statistics. Truly, we should be basing brackets on the biological stats themselves and make gender segregation a thing of the past. How will people react when the brackets reflect genetic potential rather than gender potential? Probably just as oppositional. People hate being told that someone else has a higher potential than them even if it's true. I don't blame them. But we can't live in a reality where we pretend that some aren't better built for certain endeavors.