It depends on what your definition of homework is. Practice is important in order to get the new information carried over to long-term memory. However, performing a task without analyzing what you're doing is useless. For example, if your French homework is to fill in the blanks with correctly conjugated verbs and you just look at the table with these verbs' conjugation and copy, you're wasting your time. In order for it to be useful, you have to analyze, like "oh, I will put 'suis' here because that's what I use with 'je'. Now I'll read the whole sentence, make sure I understand it and if needed, will look up the words I don't know".

Overall, homework is practice and it's useful as long as you milk everything you can out of the process.

I agree with the above.

You simply need practice. And if you have one or two lessons a week you need to do extra practice on your own. And it's going to be called homework, unfortunately. 

On a side note, my kids go to a school where there is no homework - but there is "self-study", and they mostly do it at school, they have special time allocated to it. Just a different name but associations are totally different, and kids don't mind doing it :) And when the teacher leaves the classroom and doesn't monitor them - they continue "self-studying". 

yes, for sure! Without homework you can't really absorb the language. Repetition is a key concept of the learning. 

Another interesting topic:)

Its a debated issue. I think both of them are necessary. Without a direct blueprint you can easily become confused. A good teacher who knows you well will give you homework which suits your personality. Self-studying is as important as homework. A teacher wont teach you everything without your effort but she/ he can correct you.