So, removing the delusional aspects of vicarious ordinances of slavation for those who are dead, what do you think of "genealogy work"? Certainly, it keeps many people occupied on something of unknown value. The LDS church is a big resource for many non-members seeking to uncover their ancestry.
For me, all of "the work" has been done by dedicated, mainstream LDS members of my extended family. For my own part, I had an occasion to make a tour of parts of Great Britain to find actual places listed in the genealogy. I never felt that this was in anyway important to my deceased ancestors but I found it enlightening personally. I feel it added to my sense of identity.
From a personal, secular perspective, is such knowledge useful? Can it be useful for families as well (for example, seeing patterns of dysfunctional relationships or shorter-than-expected lifespans)?