There is a long thread on the linuxcnc.org website (currently down for upgrade) under the AXIS sub heading on the use of camview-emc and cameras generally.
It is primarily for precise measurement, positioning etc.
You could use it for finding home, if you had a way of completely ensuring the same mounting position in your spindle every time, but all that would achieve is something that can be done better by a couple of homing switches.
The actual position of home is not normally important, it is the precise return to home and the accuracy of the offsets made from it that effect the workpiece.
If you overrun or stall for whatever reason lose position and have to re-home to continue, do you want to have to remove your tooling, precisely align and insert the camera and manually jog to a particular mark or just jog off the home switches and press 'Home All'?