Anderson has summarized the importance of role play in four points:
They provide the spoken language practice that is vital for all language learning.
They provide us with the opportunity to take our students out of the classroom for a "test run" of real world language use.
They allow students to become someone else for part of lesson, and thereby to leave behind their inhibitions and worries.
They involved an element of play that provides an enjoyable contrast to the course book exercises and helps to develop rapport between students.