Beats me. The reasons I hear are because their home environment is set up the way they like and they don't want to recreate it. Or the work hardware is loaded with too much "spyware" / software which bloats it. Or they don't like the forced software updates. Or the hardware is too slow (when I usually argue within me that the software being written is inefficient), and so on, and so forth. Or they don't want to deal with two computers. I see it whether the work computer is some high end workstation or MacBook Pro, or some craptop.