Group Hospital/Surgical Plans
Group hospital/surgical plans and individual hospital/surgical plans are about the worst stand alone products you can buy...which is why you do not buy them "stand alone." Where they make the most sense is layering them in with a standard health insurance plan.
As the name indicates they pay a fixed amount when the insured either ends up in a hospital or needs surgery. You have to examine the plan to determine how they work, but many will pay a flat amount from $500-$5,000 for a hospitalization and a fixed amount for surgery. You can also have plans that pay for diagnostic, emergency room, doctors visits, etc...
One of the other benefits of these plans is that they are not subject to Affordable Care Act (ACA) regulations. So, a company that is not required to offer health insurance might consider avoiding doing so and enabling their employees (especially those that would qualify for subsidies) to get coverage on their own. Then the company could purchase one of these plans, an accident plan, and a critical illness plan as a company benefit. The end result is an employee with both subsidies from the government and subsidies by way of supplemental coverage from their employer.