The idea of including medical information in family histories is a recent one. When I was writing the material I published last Christmas, I included causes of death whenever I knew them, including some that caused some raised eyebrows in our family.
Modern medicine does emphasize the genetic links which affect our daily health.
Genealogy has a role to play in informing people about the causes of their ailments, even if they have no other genealogical interests. People who do not want to spend extensive time tracing their family history but who still have a wish to document their genetically-linked conditions might find it useful. My brother's faulty retina is mirrored in several of our cousins. Naturally I was interested to find a blind ancestor in the early 19th century in England. This turned to amazement when we found that a large hospital in London is sponsoring an investigation into ophthalmalogical irregularities in descendants of a family from Eynsham, Oxfordshire.