Management
When working with an agency, they already have managers which is not the case with the freelancers. So micro-management is not required if you outsource your work to an agency.
Results
An agency might be a little expensive than a freelancer but you will get good ROI in terms of results when you choose an agency. In most cases, agencies strive for successful projects whereas freelancers focus more on money.
Data Integrity and Security
Agencies follow all the legal parameters when starting any new project while that is not the case with a freelancer. Freelancers can easily disappear in the middle of any project but agencies cannot.
Expertise
When you hire an agency, you get access to multiple experts under one roof. Moreover, any agency has more insights about different industries and businesses than a freelancer.
Communication and Professional Environment
Agencies have dedicated staff for support and communications. You can enquire about the project progress for your point of contact in a professional manner.