For Better Accessibility
If you use any accessibility features, you will want to consider installing macOS Catalina. There are new tools for voice control, low vision and ofr users that can't use a traditional mouse and keyboard.
You can now use your voice to control the mac with new grids to zoom in on and you can essentially voice control any app on your screen. The new numbered options allow for greater accuracy.
With Zoom display, you can set one monitor to be a zoomed in version and the other to be a standard resolution. This is useful for working in detail or giving a presentation.
Hover over text and press Command to get a large version of the text that is easy to read. You can set the color and font so that this works the best for you.