Apart from the obvious benefit (making 42.2 a better more up-to-date development environment for YaST), we need this to keep improving Leap while SLE-12-SP2 is already quite frozen (RC phase). The YaST codestream will not diverge (everything that gets into 42.2 will be released as maint. update or via installer's self-update to SP2) but we still want to include some fixes in the Leap media since we will not have self-update. We need this package for that.