Display lists may improve performance since you can use them to store OpenGL commands for later execution. It is often a good idea to cache commands in a display list if you plan to redraw the same geometry multiple times, or if you have a set of state changes that need to be applied multiple times.
When running OpenGL programs remotely to another machine on the network, it is especially important to cache commands in a display list. In this case, the server is a different machine than the host. Since display lists are part of the server state and therefore reside on the server machine (on one machine: server=graphics card, client=CPU), you can reduce the cost of repeatedly transmitting that data over a network.