Hi Suchindra, thanks for posing this question to the group!
By using DTM for Target, you'll have an easier time managing which pages call Target. Otherwise, it can be challenging to update all pages at once with newer versions. Additionally, using DTM for Target makes for an easier integration with the Marketing Cloud ID.
You might also find some helpful guidance in Target's documentation on Best Practices for Implementing Adobe Target using Dynamic Tag Management, as well as in Additional Resources for Implementing Target using DTM. While those are more resources for actually implementing DTM for Target, you might find some suggestions within the documentation on the benefits of using DTM for Target. Additionally, here is a recent blog post on Five Things to Know about Adobe Dynamic Tag Management
Hope this info is helpful!