I'm not exactly sure, I've just been told so by others. My guess is that since you take it as a teenager, it's considered strange to include it as an adult. But

I'm not exactly sure, I've just been told so by others. My guess is that since you take it as a teenager, it's considered strange to include it as an adult. But I haven't taken any standardized quasi-intelligence tests as an adult, so it still seems like a useful signal. People could also just lie though. I can't imagine actually confirming an applicant's SAT score.