Calling things "robots" is more about the amount of movement. Spinning in place like a washing machine sprayer isn't enough to qualify.

A paint conveyer belt is not a robot. A sprinkler system is not a robot. A CnC machine might be a robot. A conveyer belt that sorts items might be a robot. A roomba is a robot. And all of these function just fine.

I think of robots as general purpose, machines are specific purpose. When it works, we make it single purpose because that’s far far cheaper than general purpose.