Why is Machinist DPS SOOOO BAD?

[Kaonis]

At 90th percentile, aka the best 10% of people, the average difference between MCH and BRD is roughly 60 dps. Source: Susano Lakshmi

Isn't that kind of the problem though? MCH brings less utility, so you'd expect them to be able to do more damage. If BRD can essentially do the same damage with a much larger repertoire of utility, then why bring a MCH?