Playing some more, I can see how blanks are the tile version of curses. I realize now that the sacrificial spots can be used to clear blanks if needed.
A few other topics:
Potential bug: I had the relic to kill heretics that step on red gems. A heretic spawned directly on a red gem, but did not die. Is it intentional not to count that as a step? I also had the relic for opening chests from a distance - maybe related.
Suggestion: If there are more than one picks to be taken, show that in the UI. With changing relics and multiple chests being open, it can be difficult to keep track of that.