Having some of the noise diminished by putting things on your ears != being alone. I'm just slightly physically uncomfortable in a large room filled with people, especially when I'm trying to focus on something. Especially when that's how I'd spend 2/3 of my waking life on work days.

It's not to the level anywhere near some sort of phobia, it's just that when I'm in a big room with a lot of activity a portion of my brain is dedicated to concern for what's happening in the room. In an office, it's a space that I own and control. That level of comfort leads to more productivity and happiness.

I don't want to be alone in an office all the time or even necessarily most of the time, but without that cave to return to when I need to focus, life is just plain worse.

Headphones and earbuds are very painful for me after like 10 minutes. This is at a very low volume - there's just something about putting sound that close to my ear that hurts.

I'm not 30 yet and my headphone use in open plan offices has contributed to tinnitus. To be effective, the music has to completely drown out conversations. It's unhealthy.

Open plan introduces visual as well as audible distractions. Headphones don't help there.

I'm glad we have lots of small meeting rooms around. When the vibe is energetic or distracting (e.g. Party/large gathering) and I need to focus I grab a room.

Sometimes the rooms are booked but often that means the open-plan area is less noisy.

Also I wfh 1-2 days a week as needed.

Hearing damage?

A better question would be - why aren't "library rules" an option? The default should be quiet, headphones cannot recreate that, only different noise. If people wish to introduce noise, they may of course do this with headphones!