Security when you’re on untrusted network. I can trust Google to snoop my banking data and update the spending power info on my ad profile, I can’t trust the random dude in trench coat also using the public wifi when I am traveling out of my roaming coverage.
I joke of course, but the security aspect is still valid.
What is it that you're doing that is still not using some form of authenticated encryption? Almost everything is https, ssh, almost all mailservers have tls support, irc does have tls support..
What's left that needs to be encrypted by a VPN?
Strictly speaking, Encrypted Client Hello (ECH) paired with DNS Over HTTPS (DOH) can resolve this. But not many people have their systems setup this way, so it is still pretty niche.
What's the threat model here? I can think of no DNS shennanigans that would not be detectable through the authentication mechainsms in TLS (chain-of-trust). Not having to trust network infrastructure is exactly what TLS is for.
Most DNS requests are clear text, which is why DOH was introduced to secure it such that no one can snoop on you looking up something-embarrassing.com. Also, the initial request, before you get the SSL certificate from the web server, you must tell the server at 169.169.169.169 that you’re looking for the certificate for something-embarrassing.com before they can get you the correct certificate. This is why ECH was introduced. Neither of which have became mainstream yet, and so there are still some basic leakage going on.
It's not the guy in the trenchcoat next to you you need to worry about.
It's the fact that some unknown entity owns/has set up the WiFi.
Anyone working with complex network setup and admin will tell you how much you can abuse owning the network a user is connected to.
The network guys at work never use public WiFi, not hotels or anything. Neither do I, even with my much more limited knowledge of network administration.