My favourite - by a large margin - language learning app is Anki. This is an open source flashcards app, with minimalistic (one could say primitive) UI and no gamification whatsoever[1].

So yes, I see value in programs like this.

[1] to be fair, my STEM brain enjoys looking at my review statistics and charts. But they are non-intrusive and one has to actively look for them, so it's nowhere near gamification.