It is generally cheaper for people to negotiate health insurance prices through their employer as the combined company has better negotiating power than a single person.
Employers keep more productive employees if they encourage health among their employees. As such some of the insurance may be subsidized by the workplace. Employers also have an incentive to make sure that employees spend some of their earnings on health maintenance.
It is far less effort for an employee to get health insurance from their employers than on their own.
