localdeps is meant to be used as an easy way to install all dependencies of a conda package in development into a conda environment.
For example, let's say I'm developing a package named mypackage, and I want to package it as a conda package so other developers can conda install mypackage. The prescribed path to do this in the open source world is to publish as a package on pypi and then to create a feedstock using conda forge to publish the conda package.
If I'm working on closed source packages, I may need to build a conda package without publishing as a pypi package first. Here's the problem: conda does not provide a way to install a package or its dependencies listed in meta.yaml in a development environment the same way that pip does, so it becomes difficult to automate development environment setup.
So here comes localdeps to the rescue:
localdeps --conda-dir conda.recipe --env my-dev-env
pip install -e . --no-deps --no-build-isolation
Now, I only need one copy of the dependencies of my conda package (meta.yaml), and I can develop the code and have changes instantly take effect in the active environment.
conda install localdeps -c conda-forge
Note: This is not available via pip install because it depends on conda and conda-build, which are not available via pip.