An advantage of IP over TDM

If we are using E1/TDM for any interconnection, for each additional interconnection we have to lay E1s. But if we are using IP technology we just need to add a configuration to the network. For example, in TDM world if we wanted to connect to another operator (especially international) we need to lay E1s. If we are doing it in IP we can fulfill our requirement by adding an additional configuration through an existing connectivity.