The reason that Jesus went into the wilderness was to escape the temptations of society and the world.
Whilst you live in society it is very difficult to detach yourself from the values of the world.
So Jesus, and saints, and monks have always separated themselves from society in order to gain clear contact with God.
Far from being tempted in the wilderness by a non-existent devil Jesus successfully made full contact with God.
Jesus was called "out of the world". John 15:19 (NRSV)
This is also why most of the scriptures are a mixture of light and darkness - because they do not receive the full revelation of God, only glimpses.
As Paul says, "For now we see in a mirror dimly, but then we will see face to face. Now I know only in part; then I will know fully, even as I have been fully known." 1 Corinthians 13:12 (NRSV)
(Scripture quotations (marked NRSV) are taken from the New Revised Standard Version Bible, copyright 1989 by the Division of Christian Education of the National Council of the Churches of Christ in the U.S.A., and are used by permission. All rights reserved.)