Most estimates I've seen are more like 100+ hours to gain basic conversational proficiency.
You can easily end up dismissing someone’s language skills who can read the news and even books in a language yet can’t speak the language.
I'd say that simply being able to read the Francophone news (this is Canada) would give a very different interpretation of how things are seen politically. Total mastery (able to pass for a native speaker) isn't the only valid outcome.
But then what's the ultimate goal? To post "streak" badges on Instagram? I know I'm sounding cynical, and I'm sure people DO actually learn a lot using the software, but I also wonder if it was used as a supplement to another way of learning that they'd be able to communicate better.
What I'm seeing for me (and it's incomplete, it might be a fiasco in a year) is that it keeps me doing at least some daily roadwork. Once you get to reading news/magazines/whatever (that's how my father expanded his ESL vocabulary) or childrens books, you can start to work beyond. The real hazard is that once you break the chain, the incentive to do something (even when you are tired) is gone, then you probably drop it altogether. So I see the gamification of 'keep the streak' as helpful.