Its stranded copper conductor is built to handle repeated flexing better than a solid core over time, making it suited to installations where the cable will be moved, routed tightly or flexed repeatedly rather than run as a fixed, static length.
RG58A/U is rated to a higher DC-5 GHz, giving it a wider usable frequency range, while RG58 Low Loss is rated to DC-2.5 GHz but uses a foam dielectric built specifically for improved attenuation performance within that range.