The practical upshot is: 1) Many Python applications are not pinning dependencies, and even if you are personally, if jinja is a transitive dependency you migh

The practical upshot is: 1) Many Python applications are not pinning dependencies, and even if you are personally, if jinja is a transitive dependency you might pull in a breaking change. You can't if the new package has a different name. 2) You can more easily simultaneously use both to gradually transition your code to use the new API. I don't believe Python package managers have any built-in way to use an "all" conflict manager like Apache Ivy, so you need a different name to enable this.