Where and why would you need this exam? I have never heard of it before or been asked about it during my interviews. Sounds interesting.
I just stumbled upon this group, but do you still need any insight on the Qualified Associate exam? I took version 9, and just a couple of weeks ago I took the Tableau 10 Desktop Delta exam. I'm going for the Professional version next week in Vegas.
In regards to whether it is needed or not - I did not need to take the exam, but I will attest that it was very attractive when interviewing for my new role. My new boss almost always leads with the fact that I'm certified when introducing me to someone - even if they do not know what Tableau is.
I wanted a Tableau heavy role, so I got the certification. Money well spent.