You are correct that the Au pair is not a cleaning lady. In the arrangements I have seen however they do handle laundry for the children's clothes. They also help with kitchen cooking and cleanup, and whatever other cleaning is child-related.

My impression with the Au pairs that I have talked with is that the variety of duties adds interest to the work, especially during hours when the children are in school or napping.

Some who may not have cooked before also get to learn to cook this way.

At the same time, I agree with you that an Au pair is there primarily for child care help, and for the experience of living with a US family.

Au pairs agencies give good guidance on how many hours and what kinds of work au pairs can do, and also on the educational opportunities that they need to be offered. I highly recommend that anyone considering either being an au pair or hiring one work with an agency. They protect and guide both sides.