For the companies, these interviews are a cost-effective method of primary screening, and can allow for interviewees from different geographic regions. These interviews, however, eliminate some of the non-verbal cues that come from in-person interviews. There are also lunch and dinner interviews. This type involves a more casual setting, which can reduce the stress associated with an interview and give a better impression of the candidate's actual behaviors as opposed to ones that have been cultivated specifically for the interview situation. While such interviews can be effective, they are also more cost and time-consuming, plus they tend to be less consistent across candidates, placing some at inherent disadvantage to others.

This interview is predictable, and there has a high degree of uniformity of results. The disadvantage of the bread-and-butter interview is that many candidates are so well-prepared for such interviews that it is difficult for the interviewee to get an actual gauge of the interviewee's true personality.
Works Cited:

Hofstede, G, Pedersen, P., and Hofstede, G. (2002). Exploring culture: Excercises, stories and synthetic cultures. Yarmouth, ME: Intercultural Press.

No author. (2010). Generic format of a formal proposal. Dartmouth College. Retrieved February 13, 2010 from http://www.dartmouth.edu/~osp/resources/manual/pre-award/format.html