Raising children might not be what people are best at, and it's more efficient to work a job that can pay for this stranger, and to have money left over.
There aren't many qualities that disqualify a person from humanity, but being so bad at caring for one's own children that an employee would do a better job might be an example.
you can't pay someone to love your child. only you and your partner can love your child. love is nearly as important as food to them. and you have to show that love in the attention you give them - tucking them into bed at night isn't enough.