Guess "feeding" on the lawn is what you mean by "mow" in the goat case.

It's actually good to get the animals busy solving problems that benefit others rather than just let them eat, get fat and pampered like children. We all have roles we need that benefit not just ourselves but others, and the world. I don't think it's a good to assign all the roles to machines/robots.

Anyway, I wonder if goats can "mow" the grass as good as the lawn mower, and there is a possibility of overgrazing or ruinning of the lawn by the goats. I guess you'll need to move them from the lawn when the grass needs help or has been eaten down enough.
The lawn benefits from the goats "droppings".

This can be tried in rural areas and not really city or town. I will probably allow residents to use gentle, colorful and less noisy animal if I were a city/town administrator