Benefits are one of the most efficient ways to ensure work gets done at a company. By creating an incentive for employees, they must consider if doing the job is worth the compensation being awarded. Typically, the compensation is well worth completing the job and most employees will comply.
Thinking back on situations where compensation is awarded that I have been a part of in the past, I have accepted almost every extra task offered to me with extra compensation. Typically this has just meant working overtime for double pay, taking extra shifts, and working different positions that pay better. I have also witnessed scenarios where my coworkers are offered pay and half on holidays. Typically, most workers are willing to work extra if the pay is right.
Another example of a situation where compensation/benefits were involved was when my friend had got an offer at one of the top companies shw wanted to work for but had to decline the offer because the benefits and pay were not going to be enough for her to live on and pay for schooling. She even tried to counteroffer with the company to see if they would raise her pay, but they declined. This was a situation where the compensation was not enough to incentivise for the job being offered.