Activate independent voice playback, what is its function?

Although I have been a Dorico user since its first appearance, I do not know what the function of activating independent voice playback is and I cannot find it in the tutorial, can someone please clarify it for me.

It allows you to use different endpoints for different voices in the same staff.

I also need some clarification: on an instrument like a piano or similar that uses two hands to play, if you enable independent voice playback, can you then add e.g.: different dynamic symbols for each voice and Dorico will recognize them in playback?

Yes. Otherwise, dynamics, even if voice-assigned affect all of the voices.

If Dynamics are mapped to velocity, then you should certainly get voice specific dynamic playback without using Independent Voice Playback. You have to enter the voice specific dynamics carefully, using the caret to select the voice you want the dynamic to be applied to, and then by holding down the option key, (at least on a Mac), followed by Return. This should work well for a two stave instrument like the piano, but you could also use Independent Voice Playback to route each staff to a different or duplicate VST if you wanted additional control.

Thank you very much, it is great to have people so altruistic and generous with their knowledge.