On the flipside, you can have people who are overly confident, excellent telephone manner, but are utterly shite employees. You could get someone who spends a lot of time on the phone to friends, meeting new people etc, and 6 weeks after you've taken them on, it suddenly dawns on you that they are a party animal, coming in on Mondays still recovering from the weekend (or pulling sickies), unreliable for weekend work, on a go-slow on Fridays, and hard to keep them away from their mobile phone (social life, texting, Facebook etc).
As I say, unless it's a job that requires using a phone a lot, then the employer is probably not worth working for; can you imagine the rabble that will pass these tests, get jobs, and then you have to spend half your time doing their work and picking up their mess etc...
There are people I know who can "talk the talk" very easily so to speak, but are not so good at "walking the walk" and ultimately turn out to be problem employees. One person I know of, is very over-confident to say the least, got a job as a manager somewhere, probably on the basis of his interview confidence and being able to talk the talk (it was a considerable step-up from his previous position/employer and it's the way he comes across), yet within 4 months he was "asked to leave" due to the extent of problems he had caused within the workforce, and generally not being effective at doing the job properly (mainly due to the workforce losing respect for his authority).