As I understand it, it is just like in Opera. So a proxy not a VPN. I honestly find it distasteful that they may call it a VPN without it actually being one.
A VPN as you refer to it isn't a VPN either. There's no private network that is virtualized. Actual VPN software is like Tailscale.
Because people understand VPN but not necessarily proxy. It's targeted to non-tech people.
Is the proxy encrypted? If so then you might as well call it a VPN.
What makes a proxy a "VPN" again? Most popular "VPN" companies only offer a proxy that merely runs over a VPN protocol.