Professional babysitters are professional childcarers in some capacity. Sitters, for example, takes on only those who work as teachers, nursery staff, nannies or childminders in the day.
Parents in my area prefer that reassurance. They want to know that their babysitter is trained and qualified to deal with all aspects of childcare. Should their child be ill or need first aid, they want someone there who can do this.
As a babysitter, I've entertained the kids, fed them, bathed them and put them to bed. I've dealt with sleepless children, teething babies, allergic reactions, power cuts, illness, parents arriving late - you name it!
I've done all that without having to ask parents to come home. Texting them to let them know, of course, but they can rely on me to deal with it all until their return.
I do have a day job: I'm a registered childminder working 11 or 12 hour days. Yes, I do expect to be adequately paid for my babysitting when I could be at home on my own sofa, with my own family, putting my own child to bed. Fortunately, the parents I work for appreciate me and don't begrudge paying me for what I do.