You don't get any additional privacy, the only way to really _guarantee_ that you get additional privacy is to use a solution that provides privacy by design rather than by policy.
> I'm not looking for a guarantee. Probably getting additional privacy is good enough for me.
I think we can both agree that wasting your money on wishful thinking ("maybe provider doesn't log") instead of using free open-source privacy-by-design solutions is a bad idea.
The privacy-by-design solutions have their problems at well (ex: speed). It would be better to use them over VPN IF AND ONLY IF their features would be strictly equal.
As they are not, one simply calculates the expected value of both, taking into account the probability of the VPN actually logging the traffic (which should be low for VPNs with good reputation).
For some use cases, even a VPN that logs traffic would be a good idea. For instance in many countries if you download a torrent they will log your IP and try to identify you. IF you have a VPN, they won't even bother asking the provider the IP because it is just not worth it for something like that. If you were exchanging child porn on the other hand they will ask for it and take time to find you.
Not everybody needs the same guarantee of privacy or has the same risk if the privacy was to fail.
Your statement is the same as saying one should never invest in shares because the return is not known in advance, so you should just buy government bonds which are safe.
