Variations of TSP might be desired in certain real-life scenarios
In transportation-based graphs, the edge weights can change constantly when they are based on the time to traverse the roadway they represent.
It might not be necessary to visit every node in a route, so a route that visits only a predefined subset of nodes needs to be determined.
A node can be visited more than once if that provides a faster route.
Visiting a certain unwanted node might be useful in obtaining a faster route.