Asking people / animals / whatever to "hang on a minute" whilst you fiddle around with your camera case is just not going to cut it.
As someone who loves to shoot spontaneously, and many is the time that 'my' picture evaporates before my eyes as i try to switch on, point, frame and press the shutter....and that's without having a protective cover to deal with!!! However, there are many photographers who prefer to set up a shot and carry their camera(s) around in bags/cases/man friday etc and that's fine too, although it seems that many professionals have the attitude of mr mixture, that the cameras and lenses are tools of the trade and there to be used. That said the equipment is in generally good condition, although not 'concours' ready to be sold 'as new'.
I guess that it all boils down to what style of photographing you have and how careful you are with treasured equipment.
SHJ