I found screenshots on Mac OS very counter intuitive… why does it need to be 3 keys and one of which has the number 3 or 4 it? Why not 7 or 9 ? Or 1 or 5 ? Crazy
Back on the original Macintosh, which was a single-tasking system, there were special keyboard shortcuts that bypassed the current application and invoked system functions. Command-Shift-1 ejected a floppy from drive 1, …2 from drive 2, and …3 being the next available slot became the screenshot operation.