Why the organizations hire employees in direct retainership but not in company's payroll?

Why do organizations hire employees under direct retainership instead of on the company's payroll? What does direct retainership mean? Can anyone please suggest?

Employees hired on direct contract don't pose much liability on the employer as their term is predefined unless the contract is renewed.

Employers usually opt for such direct contracts when the work is of a temporary nature and treat these employees as hired professionals.

A company's payroll refers to actual employment, with all liabilities lying with the employer.