The best fitted for the environment, in terms of evolution, is the one that survives to pass it's traits along - through breeding. So in that sense yes, it does mean leaving more offspring to pass on whatever adaptive advantage it had gained. I'm pretty sure it doesn't mean we can select for greater brain capacity just by being bored from less effort required for our daily chores. Unless that boredom leads to more time and resources to devote to successful breeding, of course.

I did one of these "assessments" about two hours ago, as part of a job application. Personally, I found it laughable. The majority of the test seemed, at least to me, more concerned with detecting discrepencies in my answers than actual narrowing down any personality traits.
An hour later I received a phone call from the employer telling me they were pleased with my results and would like to fly me down (to their corporate HQ) to discuss the position further. Needless to say I'm happy with the result, but honestly a bit put off with the means of getting there. I gamed their system - all that was required was consistency in the answers and a (quite obvious I would think) understanding of what they would be looking for.
A large part of it involved me rating, from "strongly agree" to "strongly disagree" lists of words. Among those words were stupidities like "strong", "upright" and "planful".
I can understand the desire, in a competitive environment, to quantify the skills of prospective employees, but sometimes the attempt to reduce a persons personality to a metric is simply counter-productive.
The resulting "summary" didn't closely reflect my personality, and yet I'm quite certain I'll exceed my new employers expectations.