If most people did, VPNs would either be illegal or extremely heavily regulated. Just like they are in countries where VPNs are almost mainstream.
Yes, you have created an extra hop. One that bottom feeders will not take. The NSA or CCP might, though.
1) no other traffic going over that VPN at the same time, so the IP can't be linked to you at that time
2) ensure all your porn traffic goes over the VPN, and never accidentality over your actual IP, keeping an eye on things like dns leaking
You have to be lucky every time, they have to be lucky once.
It certainly won't hurt mask your online presence, but it's not the end of the story, or even the end of the beginning
How much effort are these bottom feeders going to put in, when there's so many hapless imbeciles to exploit with no effort?