The phrase "a useful example for" is correct and usable in written English.
It can be used when introducing an illustration or case that serves to clarify or support a point being made.
Example: "The study provides a useful example for understanding the impact of climate change on local ecosystems."
Alternatives: "a helpful illustration for" or "a practical case for".
It seems a useful example for the conversation we're having.
It was a useful example for Wolitzer, although not always an enticing reality.
This study can be a useful example for the application of nanocomposites that show unique surface structure and properties.
Furthermore, this novel sensing method was also expected to be a useful example for the design of other biosensing systems.
It is thick on the ground among GFS's highly-qualified staff even the school secretary has an Oxford degree.Yet GFS is providing a useful example for other schools.
The protocol developed during this trial provides a useful example for agencies seeking to adopt contextual information management into their workflow.
For a useful example of unauthorized code borrowing, see this page of the Princeton University website.
A case study is discussed which involves the execution of construction processes by means of a slip formwork system, which exhibits a large degree of repetition and, therefore, is a particularly useful example for illustrating the effectiveness of the modeling approach proposed.
SAH provides a useful example to illustrate the need for and potential of existing data related to qEEG techniques in the ICU.
The bombardment of a Lithium nucleus by protons is a historically significant and useful example for discussing mass-energy equivalence in collisions where the number of particles is conserved.
One particularly useful example for understanding Burnett's practices is her compiled score for the 1920 Paramount film Humoresque, a classic melodrama about a young Jewish violinist.
