Yes, they do have importance in an IIM interview. The act as good talking points. You have to engage the interviewer in most of these interviews and for that you need talking points. Moreover these points can help you direct the interview in the direction you want to. This also shows that you have pursued something other than academics and have aimed for a holistic development.
These certificates are also good points for your CV which is one of the most important things you will be doing after you get into a b-school. They will improve your profile as you will be able to mention them as position of responsibility on your resume.

Yeah these activities hold importance during interviews. These activities shows your diverse area of interest and during interviews you can direct the interview in these areas stating your special interest in them