It is, it's a design choice. You can do exactly the same with gimp. You can even do non destructive saves using the classic save shortcut and export it using the export shortcut (which must be cmd+e on mac i guess) when you want without messing with your current work. I personally find this more convenient than having to do a first non destructive save, save as a destructive format and reopen the first save again if you want to continue working, but it's a bit different than other tools yes