These threads seem to come up a lot, but something I rarely hear mentioned is how does this fit in the story of your application/career? MPH can benefit a lot if you're specifically wanting to focus on epidemiological work and research in your career, but if your goal is to run a successful ECT clinical and don't care about research or the public health aspect, then it's likely that it's not going to add much.
In general for any application it's good to have a variety of experiences, but it's also important to have that cohesive story/path and have experiences you can point to which support that. Take a step back and ask "What is this degree/position/activity going to add to my story?" Imo, if it helps further your goals and you can express that well, or if it doesn't but you can explain why it helped show you the direction you want to head in then it's worthwhile. If it's just another random experience or more letters behind your name to add bulk to your application, don't bother unless it's something you just really want to do.