To do what people do, without exposing humans to harms, dangers, and unnecessary risks.

Also to do the things humans don't even want to do.

And that would be the incorrect conclusion. Yes, cheaper is better, but worse and more expensive is still in the running if your boss doesn't have to deal with the human aspect and the tasks still get done. Early cars were worse than horses, but they still won out because there wasn't the biological aspect to contend with. Think about it, a human has all sort of mushy human crap to deal with. They're going to come in hung over or just tired from the weekend/last night, all sad because their mom/brother/sister/partner got cancer/died and get into fights/trouble with HR over something a coworker did and have lower output. A magic box you can put the same tasks into and get sufficiently good output back out, and not have to give it time off because it's Christmas/their daughter's ballet recital, that you can spin up 30 copies of and spin them back down with no remorse is worth way more than simply being able to pay the box $18/hr vs $20/hr to a real live human. That's why businesses are salivating at the idea of AI/robots. Not because they'll eventually be cheaper.

The robot loses an arm because your factory is unsafe? vs a human losing an arm?

What we're not ready for is replacing GDP as the important metric. There have long been known problems with GDP, and robots are only going to make that worse. A robot maid, purchased once, saves, say 20/hrs a week in household chores. That's a meaningful quality of life upgrade, but doesn't result in the GDP bump that getting a raise and hiring a service to clean your house does.