WHat is the difference between Worknote & Additional Comment

I had understandning that Worknote is intended for IT/Support agent to use so its said - Not customer visible.

But on Portal view, both Additional Comments & Worknotes are visible. I check my fresh PDI, and it has same behavior for both IT and HR portal. Users related to RITM/Incidents/ HR Case can see all worknotes added by agents.

Can someone please help me understand what is the difference?

@Ankur Bawiskar @Prasad Pagar