It has more to do with whether you think out loud (which I do and have a bit of advantage in such hiring process) and less to do with overall attitude of perfectionism when giving away finished work. I would not hire such person as consultant or support, but I worked with such people on positions that don't require much speaking with customers and they were great to work with.
Going back to the example of a doubly nested loop to determine if there are any two numbers in an array that sum to zero, it should take at most 1 minute for a smart engineer to figure out that it works. They don't have to speak before they've evaluated whether it works. The metric I use is: how long did they take to get to a solution that works, even if inefficient?