Use Case for Building Blocks
Consider a case of a building block where the ProductComprisedOf relationship with three records are defined. Since this is a building block, you will need to create multiple such structures with only a change in root the node.
In absence of the Template feature, duplication effort will be required to create a new record and link those three children nodes with the ProductComprisedOf relationship.
You can use the Template feature to create a pattern with one root template record and three non-template records. The root record then connects three children with a ProductComprisedOf relationship. This pattern can further be instantiated to create multiple hierarchies as shown in the following image:
In this instance the root template record T1 is instantiated and named as group1.
In this instance the root template record T1 is instantiated and named as group2.