The "Remembrance Process" website summarizes six reasons for the remembrance, and I agree:
1) To acknowledge the reality of death.
2) To acknowledge the emotions associated with the death.
3) To acknowledge that the relationship with the person who died has shifted from physical presence to memory.
4) To acknowledge changes in personal self-identity.
5) To ponder and search for new meaning in life.
6) To receive the loving support of remaining family and friends.
That said, please note that all the purposes of the remembrance have to do with the living. Yes, the living can but the dead cannot participate or receive any benefit from the remembrance. Psalm 115: 17 and 146:4 denies that they can.
A remembrance for the dead in Christ may have the added objective of reminding the living to follow in his or her steps.