[uniqueid]

  > Duolingo's mission [...] to maximize the time spent on the platform doing pointless tasks

  >> What makes you say that?

A clear example is the design of Duolingo's word palette.

Anyone who wanted to optimize quizzes for language-learning would alphabetize the palette, but Duolingo present words in a jumble: learners have to play 'Where's Waldo'.

By creating useless busy-work, such a design provides the illusion of language-learning. There are many other examples (eg: how effective are Duolingo's ubiquitous 'Type what you hear' exercises really?) but the word-palette design is particularly glaring.