There HAS to be a way to clear the "Continue Playing" list. Particularly when you've shuffled all your songs and just want it to stop when the currently playing song finished. I've tried the "Clear Up Next" shortcut, which does nothing that already can't be done in the UI ("Up Next" is a separate list of songs you've queued manually).
I would gladly trade the "Clear [History]" button for it if it's a question of screen real estate. I've almost pushed it, wishfully thinking it might do what I was after, so it's actually more of a UX liability for me. This seems more like a feature that should be tucked away in Settings.
My choices, now, are to attempt to manually remove each song, hoping that I don't accidentally play it, or queue up a playlist containing a single silent track (which works via shortcut 50% of the time, otherwise pops up a "MPRequestErrorDomain error1" notification)