Of course it is possible to learn a language using Duolingo, just like it is possible to get dates on Tinder, but it's just not a good method. If you're new to learning foreign languages, you'd be better off signing up for a course (but that costs time and money), and if this is your n-th foreign language, then you'd rather get a book and some boring flashcard app.
I booked the the single remaining one last year and shortly before the start they announced they will not run it anymore and instead do online classes only. Apparently the rent is too high and it just isn't viable anymore.
It sucks all around :/
Not stuff that's actually useful.
But it still builds vocabulary and is better than nothing for the price.
Just by knowing a few key phrases in the main categories and the probable answers to those in a language will help you get by a lot better than "I like to ride my bicycle in the rain on the weekends" :D
Functional fluency over grammatical competence.
plants for week walk My every uncle takes a his