User blog comment:DaNASCAT/Technical Update: October 21, 2015/@comment-5301469-20151023082022/@comment-126761-20151023114801

Glad to have helped! Often, it's generally an issue of deciding where helpfulness ends - while an extreme example, you could have icons for cut and paste, but they'd never be clicked and would simply make the UI more complex. Still, Undo is a fairly common action, and does appear in the VisualEditor's toolbar.