MD has always fascinated me, but I have always been skeptical about it. What understanding could we get from watching a complex system like a peptide evolve in time? Dissociation constant that is easier to measure than crystalize the molecule? Can we ever be sure that we have attributed all necessary quantum effects such as pi orbitals' interactions?
Biased: Was a researcher in this field...
For MD, specifically the type talked about here, we aren't taking in all the quantum effects, and that is known. Crystalizing molecules, especially large either dynamic proteins or ones in lipids is hard. Crystalizing during transitory states is orders of magnitude more difficult. MD allows us to visualize those transitory states and was used, for example, to observe the unfolding of the spike protein in Sars-Cov2 to assist in designing mRNA vaccines, because the important amino acids could be observed.
There is a lot of times where it is good enough, outpaces current experimental techniques, etc that it is the tool for the job. But it is not perfect and very rarely can stand completely on its own, in say drug discovery or other fields.