Yeah, that's why I think it's debatable. It's a lot easier to make those decisions on traffic coming from a known vpn ip, versus all vps providers in the world - many of which have corporate uses.
On the other hand - if you're smart enough to set up a vpn, you'll also be smart enough to set up ad blocking, so the point is kinda moot anyway. Plus you'll be a lot less likely to have your traffic logged opposed to a service vpn.