Solves the Range vs. Data Rate Dilemma
The physics of broadband wireless communications stipulates that trade-offs between data rate and radio range for any given transmitter power output have to be made. That is, for a specified transmit power, the data rate available (i.e. throughput) will decrease as range from the transmitter increases. This is true for any radio modulation or protocol. Once a radio reaches the maximum allowed power level, it must start dropping data rates to increase transmit distance.
Transmit power is typically limited by regulation or available battery power on the end users device. This is why cellular (centralized) networks offer high data rates close to the cell or access point, but much lower rates as you move even a short distance away. The same physics explains why the downlink data rates (from the high power cell to the mobile user) are much higher that the uplink (from the low power mobile user to the cell) in cellular systems.
Meshing, on the other hand, offers both long end-to-end range and high data rates by hopping through a series of intermediate nodes. Since the distances between each node (i.e. hop) is relatively short compared to the distance between the end transmitter and receiver, each hop can be completed at much higher data rates than is possible with a direct connection. This creates an end-to-end connection that supports high downlink and uplink data rates over very long distances. In other words, meshing lets you have both higher data rates and longer range by making radio physics work for you, not against you. This phenomenon can used to enhance any personal area, local area and wide area radio technologies.
Improved Spectral Reuse
Since nodes in a mesh network transmit over much shorter distances (via hopping through intermediate nodes) than is typical in cellular or centralized networks, they also transmit at much lower power levels. This reduces system wide interference and enables spectrum to be reused with greater density.
Non-Line of Sight and Congestion Mitigation
Hopping through intermediate nodes allows mesh networks to route around obstacles and local network congestion.