Monarch is cool but it's hard to get to when it snows. The pass closes fast and hard. At least when you go to Summit County or Vail etc CDOT and the State Patrol have tens of thousands of reasons to get the roads open and clear a day.
Eldora is cool but smaller!
Monarch Pass hardly closes more often than I70. Less resources down there, sure, but less are needed. If you are driving from Denver, 285 is generally the problematic stretch from Jefferson to Fairplay.