How helpful Duolingo was to me
I, just last week, saw that Duolingo had a Japanese class recently opened. I tried it out but already knowing basic Japanese, it was more on the easy side to me.
What I realized was that for those who have no previous experience of the language, this course does absolutely nothing for you. Think of Duolingo as a way of reinforcing (an extra credit) what you already have learned.
I see your point, but I also see that for those that are wondering if they should study Japanese or not, Duolingo can give an idea of what to expect without diving too deeply into it.
I agree in that, there needs to be improvements but it's still new compared to the other language courses. So let's hope for the future.