VPNs give nearly no security benefit as around 90% of websites already use HTTPS
which encrypts your connection. VPNs will only ever give a security benefit when you're browsing a site lacking HTTPS which is rare.
Although, a VPN can have a privacy advantage since it does hide the websites you visit from people monitoring your traffic.
When using a VPN, you send all of your internet traffic to a single server and they can do whatever they want with it. You have to trust them fully not to do anything malicious. There is no way for you to verify that your VPN provider doesn't log. Many VPNs have lied about their no logging polices before such as IPVanish.
VPNs are also very vulnerable to traffic analysis attacks.
If you want privacy and anonymity, use Tor instead.
Also see "Don't use VPN services" and "You want Tor Browser... not a VPN".