I think the value will vary based your actual institution/role, and the reaction from adcom will vary by school/person. I know that for me, EMT was absolutely worth it (I worked primarily for my college's volunteer EMS service) and gave me a leg up for the first part of M1. I talked about it frequently in interviews and the admissions dean at my school told us all at orientation that he was excited by the people with EMT experience in the class. My hospital volunteering gig, meanwhile, was incredibly boring and I never talked about it in interviews or beyond. That won't be the same for everyone though. there's some people on SDN who hate on EMTs as a useless premed experience but frankly I don't think most of them have first hand EMS experience, and I've never actually encountered that in any clinical environment so far. There are definitely better EMT gigs than others (as mentioned, transport is usually not so exciting), and scope of practice varies by location, so I would look around your local area to see what your opportunities might be before committing to the training course.