Scheduled access
An assignment opens and closes on a schedule rather than on someone remembering to unpublish it.
Capability
Assignments and exams record how a result was reached, not only what it was. Published exam versions are immutable, attempts are audited, and the gradebook does not care which source produced a grade.

An assignment opens and closes on a schedule rather than on someone remembering to unpublish it.
Group submissions and per-student extensions are first-class, so the common exceptions do not become spreadsheet work.
Submissions, grading, and returned feedback are part of one record, and each keeps its own state.

Exams carry the constraints that make a result defensible after the fact.

The gradebook accepts grades from assignments, exams, session attendance, and manual items on equal terms. Nothing is a second-class column, which means the final picture of a course does not depend on which tool produced each number.
The manual covers this as a task, with prerequisites, what finishing looks like, and what to do when it does not work.
Run it on your own infrastructure or let us host it for you. Both licences ship the same product; the difference is who operates the data plane.