Why: On a daily basis (most likely at the end of day) there is a high demand for transaction posting from a single source (file, other computation). Posting each transaction in a separate call puts stress on the connections (DB, HTTP). The connection eagerness is completed by high response time for each computation.
Eg: for a bucket of 10 loan / savings transactions the next actions are performed per each transaction in the set:
Eg (with bulk): for a bucket of 10 loan / savings transactions the next actions are performed for the entire set