Reducing a woman down to the feature you like the most is quite literally textbook misogyny.
Again, the mechanisms that created the situation are misogynistic; calling them out for what they are, even with as little tact as this commenter has, is not. Simply because in this case she's using it to her advantage doesn't shield her from criticism. If she was any good at her craft, we wouldn't be having this conversation.
lots of people have great tits and can act, so it quite literally can't be that simple.
Ignoring the fact that your logic here is a bit nonsensical, if you genuinely believe that people aren't cast exclusively for their looks and market appeal then you're simply naive. People are cast who will sell tickets. Sex appeal is something that sells. There is a very very very long list of people, and women specifically, who aged out of the ability to play teenage and young adult characters who suddenly found themselves out of work because their acting abilities didn't quite hold up when their youthful beauty faded away.
Unless you recognize and place blame in the appropriate places you are misguidedly propping up the exact systems that you're attempting to criticise. It is okay to recognize things simply for what they are and we cannot grow, in fact, if we do not.