I just ran through some of my Hung Gar forms and discovered that In Sup Yin Kuen you shift to bow and arrow stance 60 times, in Fu Hok 55, in Gung Gee 68 and in Warrior Palm 42 times. Warrior Palm has 74 stance changes total, I hadn't thought ahead of time to count the total stance changes in the others.
This high incidence of shifting to that one particular stance shows the importance of that movement in the Hung Gar system. To create a powerful punch or strike, we use the full mass of our bodies, and the muscular strength of our arm, shoulder, latissimus muscles, and our quads and glutes.
Many styles rotate the back foot away from the punch, moving some of the body mass out of the punch, and disconnecting the power of the leg from the power of the strike. In Hung Gar, we root that back heel to the ground and drive forward.
It's obvious to me from the prevalence of that movement in the forms that it is something we are intended to master that one small movement, to do it until it is automatic. So when practicing your Hung Gar forms, root that heel in and drive forward.