Feed hold is an interesting addition, especially for CNC use.
With that in mind, for machining a separate "spindle hold" is also useful - however than needs to be interlocked with feed hold, so the spindle cannot be stopped until the feed it stopped, and vice versa the spindle must be started before (and with a delay or "at speed" signal) before the feed hold can be released.
If the spindle is not controlled by the Duet board, then just a three position switch so feed hold must be set before reaching spindle hold is a simple alternative.
For 3D printing, an option stop at the end of the current layer could be useful, so the head can be moved out of the way to inspect the job or replace filament without the hotend being close enough to the piece to block the view or cause distortion??
(Just throwing suggestions in, while the subject of temporary stops is on peoples minds).