Not a single real advantage of a dedicated server for a single player was presented here. But there are many disadvantages. Everything has been said above.
If you know of any real advantages that will outweigh the disadvantages, I would be glad to hear them. Probably to the topicstarter too.
PS I can name the only case where a dedicated server provides a gaming experience that cannot be achieved in a single player game without it. This is collecting resources using a golem.
Everything I could find.