If I was rich enough and I couldn't breastfeed my own baby I don't see any reason not to. If you're working long hours in a well paid job and want your baby breast-fed it seems like a great solution to me.
I would imagine that for a single Mum who is breast-feeding it could also be a great job. You could take your child to work with you which would be fantastic. If your responsibilities ended with feeding and didn't include nannying or house-keeping it could be pretty cruisey after a few months.

ETA - thinking about the benefits of breast-feeding.... are there also benefits in being held close to feed?
Also with the concerns about the close bond.... I think that many bottle feeding mothers would argue that the bond is from being a Mum and feeding with love not from using a breast to feed.