I am of the Henry Ford mentality that I prefer commercial tools be for one main purpose. So in my shop I tend to have a different table saw for each main dado width. Etc so when I am manufacturing drawers I just go from one machine to the other and finish the whole drawer before I could even change the blades.
A way I could see being a time saver would be if you have projects that have different bits you could have multiple but identical routers that you can have each of your main bits all loaded to same exact length and just switch the router instead of trying to pull the bit out, put in new bit and align it.
This could save some time and reduce human error. Especially when the routers are not that much more expensive than some of the bits!