In short, no.
Kiddom is flexible for all educators' classrooms. So while it may make sense for 10th graders to join, kindergarteners do not need to. Teachers can use Kiddom as an intuitive planner and gradebook to design curriculum and obtain actionable analytics to pivot and personalize lessons and resources for students. When you add and grade assignments, Kiddom's reports automatically update to reflect class and individual student performance.
And no, not all assignments need to be digital. Inputting feedback from assignments carried out in class, including exit tickets, class discussions, and group activities, can all contribute valuable information for student mastery and progress.