Accent Color in SPO

When you choose one of the default SharePoint Online themes and pick an accent color, is that accent color used anywhere?

I recently chose Periwinkle as a Theme and noticed that there was no accent color.  I have had trouble finding the accent color in sites where I have selected the accent color, so I'm curious if it is important to select it at all.

In one of my searches someone mentioned that it can show up in the Hero webpart but I haven't seen this either.  Has anyone seen the accent color anywhere/have any insight into this?

Thanks!