If everything is right, they are better gaskets. They way they seal is better. But, you can’t have a rough surface and they need to be retorqued. Plus, you can get them with about any bore size and any thickness you need. That’s a big deal IF you want to keep crevice volumes down and IF you think compression matters (spoiler alert: I think it matters…a lot).
Nitrous, turbo, supercharged may be another reason because MLS is supposed to tolerate higher pressures. But yes block and head must be machined to high standard for them to work. MLS is supposed to be reusable too so that another benefit.
The FelPro 1008 met all of my needs and I didn't want to deal with potential leaks of MLS when I had no need for any of their benefits. I looked into MLS and carefully considered and went with what I thought was right for my particular setup. If I had forced induction probably would have leaned MLS.