GPS mapping requires processing and storing vast amounts of data, and this data is usually stored in a centralised server. This could cause latency issues while accessing and sharing data. On the other hand, blockchain-based decentralised applications distribute data across devices (nodes) on the network. This will reduce latency and ensure seamless access to data.
Also, thanks to a network of nodes constantly approving actions and data changes instead of one centralised entity, the application will have up-to-date and accurate information about a location. And due to the consensus mechanism in blockchains that requires verification from multiple nodes in the network, the data cannot be tampered with.
The biggest advantage of using blockchain-based mapping will be privacy. In GPS-based mapping, users have to send their location data to multi-faceted billion-dollar organisations that can use geo-tagged information for any purpose they deem profitable. They could sell your data to advertisers, and you can do very little about that.