It sounds like the study doesn't take into account cost of living. Even for a minimum wage employee, time is money. Assume for the sake of argument that this study accurately describes wage losses. [1]
Assume that the average minimum wage worker was working 2 different jobs for a total of 40 hours a week with no benefits. That's a total of 160 hours a month, or $1440. A loss of $125/month equates to $1315, or 102 hours a month at $13/hour. [1] So the worker loses $125/month and gains 58 hours. To translate that into one dollars example, childcare in Seattle costs around $10/hour.
There are of course lots of ways to save money with that free time. More sleep means fewer minor accidents leading to injury and sickness around the house. Childcare costs around $10/hour in this city, so by that metric there was basically no point in going to work before this wage increase if you had children to take care of. Saving 50 hours of work equates to saving $500 dollars. Obviously, it's not going to be 1:1, but even assuming you were spending just 15 hours in childcare would make our hypothetical worker better off, with an extra 35 hours to go to school, or just relax and keep their health.
[1] It sounds like this study is looking only at small businesses, for whom the rate is $13/hour. Since it ignores most businesses that actually must pay $15/hour, the headline seems wrong by definition.