You might need to repack a Magisk module for several reasons:
Repacking your own ADB and Fastboot module gives you the independence to troubleshoot and flash other devices directly from your pocket, turning your smartphone into a mobile development workstation. adb fastboot magisk module repack
Make your modifications
The binaries included in an older module might be outdated, leading to compatibility issues with newer Android versions. You might need to repack a Magisk module