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.
Have you ever dug a hole with a shovel?
Mini diggers are cheap to rent for a few days on a job and you can shift absolutely tons more in a single day than a labourer can do in a whole week.
If a roofing company can complete three jobs in a month compared to one job without a goods lift then renting one for each job makes economic sense, especially if it's physically easier too.