The standard low is useful for towing heavy loads............... (either 1L, 1,2,3,4,5 or if it's city traffic 1L,2L,3L,4L,5L )
<----- needed to do that when towing the Valiant
The 4.7 would be too low for towing (plus it would be pretty hard to shift out of the 4.7 low without stopping like you can with the stock low (double clutch upshift out of low to high))