I would imagine doing some exercises there are a good training of your mind. But the most helpful issue I think, is the opportunity of comparing my code with other solutions. I'm sometimes surprised how elegantly some exercises could get solved.
I think there is no general answer for that. It all depends on the task and who is doing it.
I have seen many of your posts, code and problems, so I think they are currently not for you.
IMHO you better learn about testing, debuging, general design...