Subscriber templating is part of Cisco’s Intelligent Services Gateway (ISG) template-based policy and feature provisioning which is designed to improve CPU utilization.
Traditionally, ISG subscriber policies were provisioned individually as separate features. However, because most sessions shared common policies, a more efficient approach is to create templates to improve CPU resource usage. If you’re not using ISG features, then there is no need to worry about this particular command.
subscriber templating command in your Cisco router by itself has no impact on the operation of the router itself, so whether you have it on or off makes no difference. The difference exists when you actually apply the templates.