I'm sure this has been asked a million times and explained hundreds of times, but I still get confused and forget what is for what. It's not that I want to ensure complete anonymity for myself, but if I can at least boost security a little, why not do it.

I still think you are never anonymous or totally safe online. Your data one way or another has been given away, is being given away now, and will be given away. You aren't sitting behind some VPN 24/7.

Well here they correctly said that you aren't sitting behind some vpn all the time, because a vpn, they say, gives you anonymity and security. Basically some reliable mobile proxy service gives you anonymity in terms of ip address only within the site or social network where you use it. And even that is more like masking, not anonymity.