I would like to use only my left and right mouse buttons to draw and erase notes, or to do other tasks without switching my tool (which is slower and less ergonomic). I got used to drawing notes with the left mouse button and erasing them with the right mouse button in another DAW. This is not possible in Cubase, and instead there is the right-click Toolbox which simply is a lot slower than already having the secondary tool ready to use.
The implementation I suggest is as follows: from the toolbar you can select a secondary tool, with a right click or control+click. Now you are “dual wielding” the two tools you want to use and you can just have one hand on the mouse, saving keystrokes or clicks. It is also ideal for touch screen/tablet use (I’ve ran into this using Cubase on my Wacom Cintiq).
Example: Draw is the primary tool (left click), Erase has a line under it because it is the secondary tool (right click).