As I said before, the benefit comes about when manipulating patterns on the board. An 8bit pattern can produce jaggy results, on both the screen and carving, where the 16bit won't. You want to manipulate the data with the highest resolution possible to avoid rounding errors that result in jaggy results.
This is not speculation on my part, I used to do the programming for the Pattern Editor and am very aware of the benefits/tradeoffs of both the 8bit and 16bit patterns.