There are times when the only answer is befuddlement. A perplexed voices is all about portaying those moments where your project requires the perfect "What the...?!" reaction to the unforeseen and mysterious.
Things sometimes don't make sense, or there's an event so strange and out-there that rational explanations seem to be in short supply. A perplexed voice conveys the only reaction when unusual circumstances happen and 1+1 doesn't seem to equal 2 anymore. This is a great choice for when a character needs to react to the unexplained or the unexplainable. These voices have that special head-scratching quality that conveys utter bewilderment.
There are endless reasons why you would want a character to come across as perplexed in your projects. Remember the old "I can't believe it's not butter!" commercial? While there are ways to do it more elegantly, there's nothing like "believable disbelief" to really hype people up for your new product or app. A good read is all the difference between cheesy and "Wow, I need to get me some of that," and these voice actors and actresses know their stuff. Other times, a script calls for characters to be out-of-their-minds with desbelief. Sometimes, the only viable option is for characters to throw their arms up and say "i don't even understand anymore."
It's not quite shouting, but the perplexed voice is certainly getting there. It tends to be higher-pitched and faster-paced than a normal speaking voice, conveying disbelief, frustration, and total confusion.