If you have two people doing the same work and receiving the same salary, but one receives health care benefits and one does not, then the first person is receiving a higher compensation for doing the same job.
Look at this example:
Two men, same job, same salary, work for company A.
Both have a wife and kids.
One is on company A's health plan which costs company A money.
The other is on his wife's company health plan (company B).
Company B is absorbing costs that company A would have if the man's wife didn't have benefits form company B.
The whole issue of companies subsidizing health care costs for employees has been a great cause for inequities in this country.
Initially, profitable companies could lure desirable employees to work for them by offering these benefits. This has been common place for most companies.
But many people don't have access to these same subsidies, even if they provide the same service for the same salary. This is usually because their employer isn't large enough to gain the right economies of scale.
And many companies will put the health care burden back on their employees where they can.
An employee that declines benefits means more money for the company. Rarely does it mean more money for the employee that declined the benefit.