  Flat bands in moir\'e systems are exciting new playgrounds for the generation
and study of exotic many-body physics phenomena in low-dimensional materials.
Such physics is attributed to the vanishing kinetic energy and strong spatial
localization of the flat-band states. Here we use numerical simulations to
examine the electronic transport properties of such flat bands in magic-angle
twisted bilayer graphene in the presence of disorder. We find that while a
conventional downscaling of the mean free path with increasing disorder
strength occurs at higher energies, in the flat bands the mean free path can
actually increase with increasing disorder strength.This phenomenon is also
captured by the disorder-dependent quantum metric, which is directly linked to
the ground state localization.This disorder-induced delocalization suggests
that weak disorder may have a strong impact on the exotic physics of
magic-angle bilayer graphene and other related moir\'e systems.
