Freelance editors are a good fit for one-off jobs. A clipping agency is built for steady, repeatable work.
You find, brief and manage the person. Quality and speed depend on one individual.
You work with a team. We find the moments, edit, and can post the clips, so you do not manage each step.
For a single video, a freelancer may be enough. For a steady stream of clips every month, a team saves you time.