We should support generating locale archives on the target (ideally at rootfs time using an intercept) instead of binarylocale packages. Ideally with a "no sources" option so the target can just have the locale archive and nothing in /usr/share/i18n/.
Good news is that I made locale archives work for SDKs so this is not actually that hard for images now.
RP fixed this in 8ffd93bdb09b0a4a84b27dafcd684c6abba392ed.