My parents convinced me to take the writing portion even though I was originally against it because they know that I am a very decent writer. I thought it was stupid at the time but I scored in the upper 90s in terms of percentile, and just got accepted to the USAFA class of 2023. Considering the competitiveness of appointments, it would be next to impossible that my essay score didn't have at least a slight impact on my acceptance. Long story short, I'm sure there are people with more experience than this who will be able to give you more information, but in my experience, it can definitely be helpful.
In terms of taking it if you decide you want your DD to do so, have her practice, it doesn't matter if she's the best up and coming writer in the world, the style of writing the ask for on the test is relatively unique; instead of asking for you to make a persuasive essay like the English 11 Regents, they ask you to analyze a persuasive essay, tell why it was persuasive, give examples, etc. It's harder than it sounds, analyzing someone else's work isn't generally that hard, but doing so in the way that they want can be difficult, I would definitely advice practicing the essay specifically.
Again, I'm just a senior in high school, but this has been my experience with the SAT w/ essay, if anyone else has something better to say or if I was wrong at all, feel free to correct me.
