I think that an interview in Second Life can only be considered apt in very specific situations. As a very brief introductory interview aimed at weeding out people who are purely bad for the position a SL interview would be applicable. It could also be appealing to a person looking for a position that is online, where no actual face to face interaction is needed in the job. A SL interview would be good for a tech support person because the interviewer could get an idea of how a possible employee talks and acts online.
It would be good for weeding people out because it would save time and money by not needing a possible employee to come in to the office to get an interview. If the person lived across the country an employer could get a general idea of someone's qualifications before inviting them out to be interviewed.
In the long run I think that a Second Life interview is about the same as a phone interview. It is an informal way to get a basic idea of a possible employee. I don't think it will ever reach the formality and utility of a face to face interview.