I'd like to describe as brief as humanly possible why dialectical materialism was developed by Marx in the 1st place, and then you be the judge whether it's of any use outside Marxism.
Very briefly, the historical view of Marxism goes like this. The development of societies is determined by materialistic base, which includes means of production. Everything else, such as literature and education and religion and laws, is just the superstructure on top of the base. The nature of relationships between classes is determined by their relations to means of production. Whoever owns the means of production has the power.
And here Marxist theory hits the 1st stumbling block: the relation of people to means of production, which is supposed to be the base, is usually determined by laws and customs, which are supposed to be the subservient superstructure. As the following shows, Marxists cannot simply abandon materialistic view of history to correct this.
Marxist programme continues like this: in order to rectify the injustices against the working class, workers need to rise and overthrow capitalists. They would establish "dictatorship of proletariat" under the guidance of the revolutionary leaders. And when revolution completes the revolutionary leaders would voluntarily yield their dictatorship power, and everybody on Earth would live happily ever after.
A reasonable question is why would the revolutionary leaders voluntarily yield their power? (We know now that such things never happened in any of the Communist countries, but that was not known before the revolutions happened.) The Marxist answer to that question is their view of materialism, that asserts that human consciousness is determined by the material state of being, which in turn is determined by the base. With the proposed shift of power the new just base will breed new unselfish humanity, thus making revolutionary leader so benevolent that they would happily yield their dictatorship powers for the benefit of all.
Now we see that for Marxism to have at least appearance of being non-contradictory it need to reconcile extreme materialism (base would breed benevolent men) and its relaxation (base, defined as relationship to means of production, is obviously dependent on the superstructure).
And this is where dialectical materialism comes in. If you shed all the verbiage from it, dialectical materialism boils down to what Orwell called doublethink. Stripped of the bullshit, dialectical materialism really asserts materialistic view on society except those parts of Marxist theory where materialism is untenable. Dialectical in the context of Marxism usually understood as applying "unity of contradictions", or yin-yang-like assertion that one cannot disjoint cause and effect, to the situations where the obvious is in direct contradiction with Marxist theory.
Since dialectical materialism was hand-crafted to dance around the contradictions is Marxist theory, why would it be useful anywhere outside Marxism?