I will add a sentence on the UI to explain what the current implentation really does: it always and only uses the "Is Greater Than" operator. With this information in the UI people should not be confused. With this operator you can easily do a "Is Greater Than or Equal to" operator by changing the "condition value". For instance if you want a break at 10 put 9 in the condition value, etc.
I believe it's usable as is because the other operators don't make much sense (if any) with this rule condition. IMO, Only the "Is Greater Than" and Is Greater Than or Equal to" operators make sense with "X Quantities of Product".