Update README.md

README.md

@@ -7,6 +7,6 @@ This is essentially a metapackage of three packages:
 - some [custom tools](https://github.com/neuropoly/spinalcordtoolbox/blob/master/dev) for research and development
 - [ctrDetect](https://www.creatis.insa-lyon.fr/site7/en/ctrDetect)
 
-We distribute them together because it simplifies our package manager, `sct_download_data`, to only have to track and know about one big file.
+Unlike a traditional metapackage, instead of including links to the contained packages this directly copies them into it. We distribute them together because it simplifies our package manager, `sct_download_data`, to only have to track and know about one big file.
 
 See [.github/workflows/build.yml](.github/workflows/build.yml) for the build script, and the links to update to change the included versions.