The structure of Sonata Form - consisting of an Exposition, Development, and Recapitulation (sometimes with Coda) - gives ample room for the execution of a musical argument. In the exposition, all musical material and ideas will be presented, or 'exposed' to the listener. The Development then allows the composer to develop his ideas, before the Recapitulation closes off the piece.
Moreover, this structure allows the composer to create Tonal Conflicts and interesting use of Tonality, which can later be resolved. The Exposition will have two groups, in contrasting keys. The development will then run through several foreign keys, avoiding the two keys from the exposition. The Recapitulation will Recap both groups, but now in the same key, thus resolving the tonal conflict.