Different horizontal and uneven bars require different giants speed. Advanced gymnast must be able to speed up or slow down their giants at will be means of the power utilized to execute their taps.  The straps are a perfect opportunity to practice long sets of giants where the athlete may change from fast to slow giants and vice versa several times in each single set.  This same principle of practicing and matering back giants at a faster or slow pace  also applies to the front giants.