When would you use it?
- to keep my Cleves from producing the zzzzip,
- to get some roll on uphill shots,
- to maximize the effect of punches from heavy rough,
- to fine tune shot length when a yard or two are missing,
just to name a few.
Depending on the situation, to get more distance driving into a frontwind...
I use top spin when I want a lower ball trajectory and/or more roll out after the ball lands.
A lower ball trajectory can help with head winds.
On some holes (think St. Andrews), and when landing on down slopes, top spin can add significant distance to a shot.