Tracking down those aunts and uncles who had no descendants is advised because it helps give the researcher a complete picture of the entire family and it helps all members of the family to be remembered. Those are excellent reasons. But there’s another reason.
Some record on that relative with no children of their own could provide information on those relatives you can’t find out more about. This 1980 death certificate for my aunt listed a sister-in-law as the informant–complete with residential address in 1980. Had I been unable to track her down, the reference would have been extremely helpful.
Any record on that relative with no descendants could tell you more about your relative’s life. It could also provide information on other family members as well.
The drawback is that sometimes death certificates on these relatives only have “hospital records” as the informant. But you will not know until you look.