I do it, Mia, because
1. It's one of several ways to comply with FL state requirements.
2. It's practice for DD8 since she'll be taking standardized tests her entire life.
3. It's merely one of several tools I use to grade myself as a teacher.
4. I know where to focus the following year.
I can certainly understand why people don't use them. If it wasn't a state requirement, I'd probably do them every 3 or 4 years instead of every year.