No. I suspect my writing skill to be fairly well developed over the forty-five years I've been into Creative Writing as a hobby or pastime. What is does do is give you plenty of practice in putting together essays - which Hubpages calls Hubs - and thereby giving you the opportunity to find, research and then present what you have learned. If you treat each Hub that you create that way, you're bound to gradually improve.
This is because 'practice makes perfect.' No one ever gets to 'perfection.' Even the most famous writers have their literary critics who can find some fault with what has been written. But the more you write, with the endeavour of always giving it your best shot, the better you will become.
Also, these Question and Answer pages are good. I'm into anwering questions most times that I log on. It's stimulating, and it widens your interest across a whole spectrum of topics you probably wouldn't bother with otherwise.
Hope this has helped you.