There are several reasons why companies and individuals might choose to hire a freelance cinematographer for their projects. Some of the main factors include:

Cost-effectiveness: Hiring a freelance cinematographer can be more cost-effective than hiring an in-house crew or production company, as freelancers typically don't have the same overhead costs. This can be particularly beneficial for smaller budgets or for companies that only need a cinematographer for a specific project.
Flexibility: Freelance cinematographers often have more flexibility than in-house crews, as they can typically work on multiple projects at once. This means that they can often start or finish a project more quickly than an in-house crew, which can be beneficial for companies with tight deadlines.
Specialization: Freelance cinematographers often have a specific area of expertise or a unique style. By hiring a freelancer, a company can get access to that expertise or style without having to build an in-house crew with that specific skill set.
Control over the final look: Freelance cinematographer often have more control over the final look of the project, as they are not tied to the vision of a specific production company. This can be beneficial for companies that want a particular look for their project, but don’t want to compromise on their vision.
Networking and Fresh perspective: Working with freelance cinematographer can also provide a company with access to a wider network of professionals and fresh perspective, as freelancers often work with different people and companies throughout their careers.
Scalability: Hiring a freelancer allows companies to scale their production needs up or down as needed, rather than committing to a fixed in-house staff.

All in all, the reasons behind hiring a freelance cinematographer depend on the company's specific needs, budget and timeline.