And often they’re there so no one can plausibly say they didn’t know what they were doing or stumbled into it accidentally. You can’t “accidentally” go through a door with a padlock on it.
I’d guess it’s something similar with this dongle. You can’t “accidentally” run the software without the dongle.
Copy protection was also generally less robust for educational software, since it sold to generally law-abiding folks (parents, educators, etc.). Never saw Rapidlok or V-MAX! used for educational software on the Commodore 64, for example.