Low-voltage islanded microgrids are an attractive solution for remote electrification due to their flexible and autonomous nature. Like all power systems, high capital costs must be amortised through customer subscriptions. Although a communication system adds capital cost to a microgrid, it has the potential to reduce overall capital and operating costs because improved metering and billing reduces over-capacity, and enables coordinated control of microgrid components. This paper surveys digital communication for microgrids and provides descriptions of applications, a technology comparison, and a cost-benefit analysis of the value added to energy delivery by the addition of a communication system of a particular bit rate and latency to a representative low-voltage islanded microgrid. The study concludes that investment in a low bit rate, medium latency (1 kbps per customer, 100 ms) communication system has significant economic benefit to both customer and utility by enabling services such as automatic meter reading and demand side management. In a solar PV-dominated microgrid, the addition of a communication system may reduce the levelized cost of energy by 32%.