Not good for your paint. Too much pressure. Won't get all the dirt off. Will likely push water past your window seals and into the car.
The only way to get your car truly clean and prevent damage is to hand wash. If you rinse it really well and use a very soapy sponge with a gentle touch, you shouldn't be leaving swirl marks.
You might be getting swirl marks because you are not getting your car completely clean and then you are drying it and accidentally rubbing the slight dirt residue into your paint.