Maybe you just want to test a NAV web service. Maybe you want to periodically carry out an unattended task (Windows Task Scheduler!) in NAV, but you can’t use the NAV Application Server (NAS), e.g. because the task uses .NET Interop, which can only be executed on the NAV Service Tier (NST). Or maybe you are using a version of NAV where the NAS doesn’t even exist anymore.