Hello! I am exploring the use of PCoA Unifrac plots in Qiime2 with some 16s amplicon data from fecal samples of different species and while researching a bit about this I have come across a few people who say to use unweighted Unifrac plots instead of weighted to compare sample groups if you are looking to find a biomarker. Would anyone have some insight as to why?

My understanding is that weighted Unifrac plots consider relative abundance of taxa shared among samples, while unweighted only considers presence/absence of taxa shared between samples. So let's say you compare fecal samples from two different species of bird using a weighted and unweighted Unifrac, wouldn't you want to take into account relative abundance when taking a biomarker approach?