If I had the discipline to do it I'm sure I could get further with other techniques, but for me the biggest feature of Duolingo is the way you don't need very much discipline at all to make progress with it.
"You don't need very much discipline" and "5 year streak". Sorry, but is my definition of discipline that off? You managed to have 5 years of discipline. That's the reason you managed to learn a language, not because the duolingo gamishittification does miracles.
The gamification is what helped me make it this far. Remembering to pop open an app for a few minutes on your phone takes so much less discipline than any other form of language learning I've tried in the past.