I really appreciate this post since I think many discussions about VPNs are misleading or treat them as a magic solution to all problems.
I think you’ve given a fair outline of what a VPN.
But, being the Internet, I have a few thoughts,
Hiding your IP address: VPNs will replace your IP address with a random IP address assigned by the VPN provider.
I don’t think the word “random” is needed. The IP address a VPN assigns is no more random than the IP address your ISP assigns. I think someone could see random and assume more security, which would be incorrect.
IP addresses are usually static, meaning it never changes, but sometimes your ISP may assign you a dynamic IP address, which will change every few months or so.
Last I knew ISPs still charged for static IP address, so most would be dynamic. Although often times a dynamic IP address is de facto static, since an ISP will never change it.
If you open up ports on your router (for various purposes), it can leave your network vulnerable to certain attacks as long as the attackers know your public IP address.
I think this should be a separate bullet point, since this is clearly security and not privacy. I think as a security point it needs further discussion. Really I imagine this only comes up in peer to peer connection scenarios. I don’t know if the denial of service attacks of old are still relevant.
Encrypting your traffic: VPNs can allow your traffic to be encrypted, so that your ISP or other people connected to the same network can’t see which sites you visit or (in some cases) what data is sent. The reasons why this is important are too long to list, but you can work it out on your own.
I think it’s important to clarify who you are encrypting your traffic from. Generally your traffic is already encrypted. DNS is often not encrypted.
Re random IPs,
Sure, but my point is there is no such thing as a “truly random” IP address. You receive an IP from your ISP or VPN provider, that provider has a pool of IP addresses. Dynamic means you get one from the pool. Static means you get the one reserved for you, from a similar pool. The security/privacy benefits are nearly zero and not worth highlighting as an advantage.
Re static IP,
https://nordvpn.com/blog/static-ip-vs-dynamic-ip-address/ says,