Spin instruction is the standard starting point for all beginning aerobatic programs. In addition to providing an essential basic maneuver, the training greatly increases safety and confidence for pilots denied exposure to spins during primary instruction. The US is the only major nation that does not require spin training for its Private pilots, despite the fact that spins have been around since the beginning of powered flight. 
A spin is a natural "autorotation" that builds from other, more desirable, design characteristics of fixed wing aircraft. Any airplane that can be stalled can be spun. When pilots view spins with mistrust, it is due to the fact that not every spin is recoverable--a circumstance usually traceable to inadequate control surfaces. 
This animation traces spin development through the first full turn; all certificated single-engine aircraft in the US are capable of recovery at this point. In subsequent rotations, the nose will continue to rise until stabilizing approximately 60° below the horizon. At that stage, recovery is not possible for all aircraft. 
Aerobatic airplanes are naturally built with the controls necessary for recovery at any stage of spin development, and spins are a standard figure at every level of competition.