The study seems to indicate that reading is more effective / engaging.

My gut tells me that film and television is to reading as a snack is to a meal.

there are not 40+ episodes or even multipart movies of discworld, sadly. And while there are a few adaptions, I don't see how spending less time absorbed into the fantasy would be desirable ;)

Discworld just could not be adapted to the screen... you'd lose the puns, the outrageous descriptions and the hilarity of it all. I mean... maybe if it was stylistically something like A Series of Unfortunate Events with the over-the-top costumes, make up, and set pieces... but it still wouldn't quite capture Pratchett's little piece of un-reality.