An important aspect of rapid cycling is cleaner product.
Rapid cycling leaves less time for primer extension at non-specific annealing sites.
The amount of nonspecific product is directly related to the time spent at low temperatures 1 Wittwer, CT, Garling, DJ 1991. Faster cycling produces cleaner electrophoresis gels. Cycle sequencing reactions done in the RapidCycler are cleaner and more readable than parallel reactions done in a conventional heat block cycler 2 Swerdlow, H.K. Dew-Jager, and R.F. Gesteland. 1993. Rapid Cycle Sequencing in an Air Thermal Cycler. If low specificity is desired, the RapidCycler can be programmed for hold times.