It is not used as evidence. It is a graphical representation of a concept. It is a way to take a highly complex idea and represent it in a way that is easier to process or understand.
Yes, phylogenetic trees have indeed been used as evidence for evolution. They were said to validate Darwin’s prediction of common descent...that is, until the Evos finally came to the conclusion, long predicted by Creationists and IDers, that said phylogenetic trees cannot be used as evidence for anything of the sort. Now they are even talking about a “Biological Big Bang” as the “generative mechanism” that led to the diversity of life! And as the author rightly points out, this generative mechanism sounds an awful lot like the historical Genesis recounted in the book by the same name in the Bible. In the end, God’s creation resists ALL naturalistic explanations of its origin. And as such, all God-free explanations for the same are bound to fail.