Because usually people don't know what they are doing and they will end up committing files with broken library links.
Superseeded by BAT🦇
BAM has been superseded by Blender Asset Tracer (BAT). BAT supports many of the features of BAM, and is actively being developed. All open tasks regarding BAM are closed, and the project will be set to read-only. If you use BAM in your own project, please consider migrating to BAT.