FF6 - Brave New World

As a general note, more speed = more turns + turns come sooner. Thus, more battle wins and faster, too, since you can act sooner and just delay if you need.

High speed in FFVI is like high initiative in certain other games. It lets you go first, determine who's next, and what happens to them.

This is why, when possible, I always fully outfit my team with Sprint Shoes!