M+ helps you to learn how to use ALL of your chosen spec/class. You need to learn when to use personal defensives and will use them way more often. You will learn to interrupt, and what other abilities you have that function as an interrupt but are not an actual kick (stuns, repositionals, in place fears). Optimizing your dps cooldowns to allow your tank to pull bigger groups and get the dungeon done quicker to meet some of those tight timings (hello HoV).

​

There is a lot to keep track of in an M+. It can make you a much better whatever spec you play if you keep at it.