It gives you financial security if you decide to tell your employer to go fuck themselves if they want you to work too much overtime. Since you no longer absolutely need a job to live, you have a stronger negotiating position with employers.
The problem is that if everybody decides to tell their employers to go fuck themselves, nothing gets done, and then there are no goods and services to buy.
And then the employers will have to stop abusing their employees to get them back.
The majority of people have a basic need to work in some form or another, regardless of compensation.