Effigy of Ravana is burnt on Vijayadashami, in India at many places.
he is considered an Evil and a Demon , why then is he worshipped with so much reverence in India ?
He was great in many ways,
but the one evil he committed in desiring / abducting Sita -
made him one worthy of contempt and deserving maximum punishment.
He is an object lesson to all -
both the evil-minded,
and the good-natured.
His effgy is burnt just to remind human that coveting is to be condemned.