In other design tools, including Photoshop and Sketch, you can hold the shortcut for a particular tool, take a single action with that tool, and then release the shortcut to return to the default select/move cursor. (This is actually the default behavior of tool shortcuts in Sketch, even when the shortcut is released, which I prefer; Photoshop allows it if the shortcut key is held until the action is completed.)

This speeds up the workflow considerably, since the default cursor is the starting point for most actions I will take in working with any file. In particular, being able to hold Z to jump zoom levels (in combination with holding Space to pan) without having to switch back to the default tool is a hard-wired habit at this point. Not having the option is jarring for me.