I don't know why they are uncommon here as lawns are just as popular as they are in other countries.
Labor and capital(robotics) are substitutes. Thus in a cheap labor market (USA) anybody that would use a robot instead simply uses human landscapers.
It is quite common in the USA to see humans doing what would be automated work in First world countries.
I'm not sure though --- I think it might be that Americans tend to have a different relation to their lawns than Europeans. I was surprised to read that mowing your lawn on Sunday is illegal in Norway, with a silent robotic mower being a legal workaround: https://www.newsinenglish.no/2015/07/27/conflicts-arise-over...
https://en.wikipedia.org/wiki/First_World
I get what you're going for, HN loves to hate on the US.
> It is quite common in the USA to see humans doing what would be automated work in other First world countries.
I get what you're going for, HN loves to not give any benefit of doubt.
Are these safe enough to justify use?