I do that daily. Most of the services we run consist of 1 - 8 application servers ( often closer to 2 than 8), so things like Docker doesn't make much sense. Even though we of cause try to automate as much as possible, using things like Ansible, we often log in to servers directly to verify changes. Database servers are normally manually managed, to some extend, so we'll always login directly.

When I'm on-call and get an alarm on a server, checking that colleagues aren't logged in is normally the first thing you do. If a service fails it's more often than not someone doing maintenance, and they just forgot to tell you, or disable monitoring. And as someone else pointed out, also check disk usage.

Hacker News can be a little blind to the fact that most software projects are rather small and modern servers are really powerful. It's actually pretty rare that someone manages enough infrastructure for a single service that logging isn't a viable option.