I'd guess that this is to ensure one abusive user doesn't get every other user blocked from a large service (say, Google) for botting over the VPN and constantly rotating IPs.

It's a practical measure, but definitely has a privacy cost though.

I imagine there are a bunch of things on the internet that break if you start trying to connect to them from varying IP addresses. Things like the various CAPTCHA schemes and rate limiting etc, IP reputation etc.

> Exit IPs are a public information.

Yes, obviously.

> VPNs are snake oil

Huh?

VPNs are not snake oil. They transfer the trust of your internet activity from a place of low-trust, your ISP, to a place of high-trust, ideally a trustworthy VPN like Mullvad, IVPN, or Proton. Among other benefits. If you don't like your ISP creating a profile of you and selling it to target ads to you, you should use a VPN.

>Should I use a VPN?

Yes, almost certainly. A VPN has many advantages, including:

1. Hiding your traffic from only your Internet Service Provider.

2. Hiding your downloads (such as torrents) from your ISP and anti-piracy organizations.

3. Hiding your IP from third-party websites and services, helping you blend in and preventing IP based tracking.

4. Allowing you to bypass geo-restrictions on certain content.

(https://www.privacyguides.org/en/basics/vpn-overview/)

> VPNs are snake oil

The most generous way of reading that would be the fact that every YouTube pushing for a VPN as an essential tool just to use the internet outside of your house without getting hacked is a big exaggeration or fear mongering but there's good reasons for using a VPN for a lot of reasons and it's not snake oil.