In a Weighted Graph, every edge has a "weight" (or cost). It could represent:
Distance in kilometers (Google Maps).
Time in minutes (flight connections).
Cost in dollars (shipping routes).
Latency in milliseconds (network routing).
BFS finds shortest paths when all edges have weight . With varying weights, you need Dijkstra. It always picks the closest unvisited node, ensuring you process nodes in order of their shortest distance from the source.