Pradeep,
It depends on what the SQL scripts are designed to do. In certain cases, there are advantages of using SQL scripts over DS jobs. But to come back to your question, here is what I can think of:
1) DS has many options to manage memory efficiently. You may see performance improvements if using DS over SQL.
2) The DS UI makes the code very easy to understand to and you can easily add/edit complex transforms.
3) If you need to add any disparate sources in the future, DS allows to so quite seamlessly.
4) You can simply add the existing SQL to a dataflow in the existing dependent job which which will allow you to complete two steps by the execution of a single job. This obviously reduces dependency and also make error handling and correction relatively simpler.
Cheers,
Chaitanya