The paid teachers I have hired on italki have been excellent.
The paid community tutors I have hired on italki have been excellent.
I have met about half-a-dozen language companions on italki and several of them have been very helpful and very worthwhile.
The various online "community" sections ("notebook," "answers," and "discussions") are what they are. They are pleasant. They add some enrichment to the language learning process. They are not a method for learning a language.
italki is primarily an online marketplace for matching students and paid teachers. The way you learn a language with italki is to hire a teacher.