The lease is $3000/month which even in an area where unskilled labor is really expensive I don't see how this would be practical because you'd probably need at least two to keep up with a human- and the human could sweep when it's not busy.

For robots to make sense for a task it probably needs to be something with fairly consistent and constant demand which is the opposite of dishwashing which will be in heavy demand a few hours a day and light or no demand the rest of the time.