I think having a hand cranked washing machine like that on on some multi-day trails is a great idea, assuming it's at an access point like a parking lot, public campground etc, and you use eco-friendly soap and there is an appropriate waste water disposal plan. If It came with a hand cranked wringer, you could hang your semi-damp clothes on some bushes to finish drying or drape them over your backpack as you walked.

If no wringer is available, you will have to hand wring them.