Old game designers were just as intelligent as game designers today.
Their games lacked multi-media assets compared to today, but the designs are just as intelligent.
Oregon Trail was simple and very fun, and had various levels of mastery, and enough diversity (budgeting then hunting and vice versa) that it made it entertaining.
The short: It was around since 1971. It was basically an AAA game on a teleprinter. It was random enough that you couldn't "game" it by getting calculations right. It calculated the accuracy of your shot by your speed of typing. It rang the bell when you got a hit.
Basically, it had a lot of 'juice' for games of that era and was an easy hit (pun intended). Some teachers would have played it by the time they became teachers. There's probably some nostalgia and they'd have brought the sequel to schools.
It was a time before anyone had a 3D online multiplayer video game system at home. Before home internet. People were not raised on tablets so seeing the screen react to your input was still a magical moment.
I don't feel it helped much with history. Other than solidifying the "Oregan trail" happened into everyone's head.
Oregon Trail in particular seems to have been widely available. Maybe they did some bundling when the schools bought the computers?