Unemployment benefits only kick in for people who have lost their job through no fault of their own, though state laws probably vary here. If I quit because my boss is a jerk, or I’m not being paid enough, or many other reasons, I am not eligible for unemployment. My employer has a lot of power, since finding a new job can take a lot of time that I may not have given a full workday and other responsibilities.

The vast majority of people who receive unemployment had an unplanned job loss, which already puts them at a disadvantage both planning-wise and psychologically. If instead you KNOW that you will receive income when choosing to leave a job, you are more able to prepare for how it will affect your lifestyle.

You don't qualify for unemployment benefits if you refuse to take a job due to unfavorable terms.