Welcome to Amiga games, in many cases the floppy would contain the boot loader that would directly jump into the game.
At least on the Amiga 500 you would not go through the trouble to start Workbench, only to load the game, unless you were a lucky owner of an external hard drive.
I recall many IBM-PC games are bootable games. I inserted a floppy , resets the computer, and then it directly boots into the game. The disk must contain a boot sector and drivers and such.
PC had bare metal games too. They were called “booters” and you can find an entire category of them on mobygames:
https://www.mobygames.com/platform/pc-booter/