I disagree with the critics who say DM is pointless if you don’t intend to work as a DM. I’ve just completed my DM. I’m on 98 dives, of which 18 were DM training dives and 10 were fun/practice dives during my DM training.
I started with no desire to work as a DM, and I just thought it would be fun, I’d get to do more diving and I’d get to learn more, working with instructors. DM gave me all of that. The main consideration is going into it with your eyes open and understanding whether it will give you what you want.
DM made me a better diver, period. In terms of specific individual dive skills such as buoyancy I could have worked on those in other ways such as fun diving. But having a structure to my progression got me out diving more, and I had a lot of time learning from instructors. It also helped me to perfect the basics. I also encountered lots of new situations that I wouldn’t have otherwise encountered apart from in training, such as a real life aggressively panicking student diver spitting out their regulator underwater, things like that.
But I think the next step in being a good diver is about dive leadership. I improved my situational awareness, group leadership, wider understanding, task loading and wider skills (I have no desire to get into tech diving or full team diving; I enjoy recreational diving for what it is, and I want to be good at it, but that’s where I stop).