Why is it appropriate to compare the process of evolution with branches of a tree rather than with a ladder?

The process of evolution is more appropriate to be compared to a tree than a ladder because, a ladder depicts vertical, linear process with no deviations and is something that moving forward or is always progressive

However evolution does not occur in a linear fashion it is more of having a common ancestor and its decendents, which then deviate out to give rise to more decendents like the branches of a tree. It is not always progressive as certain traits absent in organisms at the end of the branch would be present in the 1st common ancestor