At Weber State, you are admitted, but you still need to enroll in classes before the semester starts and you need to complete orientation to do that. So if you do not complete the Confirmation of Interest (COI) form, you will be asked to do so at the in-person orientation before you can enroll in classes.
At the tech colleges, you are admitted to the school, but they need to know what program you want to enroll in. The Confirmation of Interest (COI) form gives them the info they need to reach out to you and get you enrolled in the right program before school starts.