I have, over the years, run into good Catholics who because of the superficiality of the social trappings of funerals thought it would be better not to have one, better to plan not to have one for themselves as a testimony against the often ridiculous spectacle of funerals. They claim that funerals are for the living.
Well, the answer is that funerals are a testimony to the reality of God and the hope in the resurrection of the body, and, above all a suffrage for the dead. It is good to have funerals because they are efficacious for the purification of the souls of the deceased: the prayers and especially the Holy Sacrifice of the Mass (cf. 2 Maccabees 12:39-46). You should want people to pray for you when you die and it is good to provide them with an incentive to do so, which is primarily the funeral ritual.
Furthermore, there is a profound reason for having funerals for the sake of the living. The funeral, planned and provided for by the deceased is one last and posthumous spiritual work of mercy: to console the sorrowful. It may also be an occasion to posthumously exercise other spiritual works of mercy (if the funeral guests are particularly unworthy and undeserving of any acknowledgement or reward by the deceased: when the surviving family and friends have been particularly unjust in their relationship with the deceased): to forgive all injuries and to bear wrongs patiently and to pray for the living and the dead. In this case it would be the dead (vicariously, through the funeral ritual) praying for the living! in the knowledge that even the ingrates and the undeserving (especially they) need God's grace and mercy, which often come through the efficacious rites of the funeral to the survivors of the deceased. It provides a final occasion to exercise the "love thy enemies" and the "do good to those who persecute you" and "reconcile with your brother.
Plan your funeral for your own sake, that, through the ritual of the Church God's grace might forgive your own sins. And plan your funeral for the sake of the living: that the grace of God might touch, inspire, transform and forgive them through the same rites at which they assist, even their hypocrisy and neglect and superficiality. Funerals might be a final and deliberate act of indulgence granted by the deceased upon his survivors. That also is highly recommended.
One last thought, in another vein, on the value of funerals. Every act surrounding the respectful treatment of the remains of the deceased is an implicit act of divine worship and an expression of hope for life after death and of the resurrection of the body. Only in the light of God and eternal life and the bodily resurrection do any funeral rituals of whatever kind make any sense. Funeral rites are an expression of man's eternal instinct (we are by nature men who believe that the tomb cannot and must not be the end: God has made us so, from the beginning of man's creation on this earth in every land and in every culture: therefore all funeral rituals throughout the vast history of man are types pointing to the glorious Resurrection of Christ which is the source of our own definitive hope in life after death in the living flesh).