Times have changed.

They do work, however I believe they can potentially cause swirls/light scratches. If you end up pulling some dirt over the car with a squeegee or chamois. Most people use a large fluffy dry towel these days.

If the dirt has survived two snow foaming and rinse cycles, and then a soapy mitt and another rinse then I think it deserves a go at the paint if it then gets dislodged by a flaccid windscreen wiper wannabe.