Answer to Question 1
Guided imagery is used primarily in counseling contexts to promote relaxation and stress reduction. It can also be used to foster insight or help clients visualize a more positive future.
Answer to Question 2
A recent meta-analytic review found that both progressive muscle relaxation and meditation are more effective than autogenic training for anxiety reduction. So it may not be the best deep relaxation method for anxiety reduction, but is a viable alternative if the practitioner does not respond well to progressive muscle relaxation or meditation training.