The game folder stores your actual installed game files (the equivalent of a digital game install). The workbin folder stores derivative data that the emulator generates to run those games faster.
: If you have a dumped game folder, you must place the work.bin file in the sce_sys/package/ directory before compressing the folder into a .zip for installation. vita3k workbin file
Vita3K uses workbin files to load and execute shader code, which is essential for rendering graphics in games. When a game is launched, Vita3K loads the required workbin files, which contain the compiled shader code for that specific game. The game folder stores your actual installed game