Depending on the task, a human doing it may be highly discouraged by H&S regulations, or the insurer.

Even on individual small building sites in France I'm now seeing mini-diggers instead of human shoveling, everywhere, or tile elevators (for a 3 man roofing team!) instead of the stereotypical exploited immigrant manual labourer. These are justified by insurers quoting such a high price for covering the expected accident and long term health costs of human shoveling or tile carrying to roofs that buying the machines is cheaper.