VPN on router vs. VPN on dedicated machine

I admit I'd be a bit of thread hijacking... what's the benefit of adding the vpn responsibilites onto the pihole device, say IF your router already is configurable or... already configured w/ VPN.

Is it no different than how the router can handle DHCP duties, and the Pihole device can do it too and you just pick and choose?

(Moved to a separate topic, since your question is not related to Pi-hole at all)