That's a serious point of frustration for me. Having an option to use anaconda, fine. Forcing it on your users, meh. I already have a working system using virtualenv and pip, why force another on me?
For installing it, yeah pip is great too, but for building conda includes third party tools and libraries and stuff. e.g. in order to use the MPI backend for PyTorch's distributed processing you need to build it yourself and conda just makes it a bit easier. That and I had a real bad experience with trying to build Tensorflow (and Bazel) to run on an HPC cluster.