The main advantage of face-to-face or direct interviews is that the researcher can adapt the questions as necessary, clarify doubt and ensure that the responses are properly understood, by repeating or rephrasing the questions. The researcher can also pick up nonverbal cues from the respondent. Any discomfort, stress and problems that the respondent experiences can be detected through frowns, nervous taping and other body language, unconsciously exhibited by any person.
This would be impossible to detect in a telephone interview. So face-to-face helps the interviewee to get the desired results and help them the expression of the person to whom they are interviewing. By reading the facial expression of the respondent the interviewer can easily understand what the respondent want to tell them about any thing.
The main disadvantages of face-to-face interviews are the geographically limitations they may impose on the surveys and the vast resources needed if such surveys need to be done nationally or internationally. The costs of training interviewers to minimize interviewer's biases for example differences in questioning methods, interpretation of response are also high. Another drawback is that respondents might feel uneasy about the anonymity of their responses when they interact face to face interviews.