To me, the most notable difference is "confidence" in what happens when leadership change. The next in line is already decided in a monarchy, often already well

To me, the most notable difference is "confidence" in what happens when leadership change. The next in line is already decided in a monarchy, often already well-known by the time of the official handover. Dictatorships tend to fall into chaos when leadership changes, and the current leader tends to remove any potential leader replacements to remove threats to their authority.