I prefer working in person iff I have a door.

Doors are a necessity in the work place and I hate open offices. 1 other person is okay but I'd rather a small room than no room.

A door let's be close out the rest of the world when I'm in the zone. There's time for collaboration but there's time for isolation. In a physical place I can turn off all notifications and close my door. I can make a space where there's low physical distractions like noise or people walking in front of my desk (or talking 5 feet away...) A slack setting of "away" is interpreted as either "eh, they'll probably answer" or "they forgot to turn it back off" (or they don't notice/care)[0,1]. But a physical door, people are much more cautious about knocking on it when it's usually open. It's not the same thing as a busy sign.

But I also don't think a door should be usually closed. It should usually be open. Indie collaboration but also respect your coworkers. A door is a great communication tool that you just can't get online.

[0] and for the love of god, do not hit me up with "hey". It's an asynchronous messaging system. I'll read the notification as it comes across my screen. Don't try to become synchronous with me that way. Call me, physically find me, or ask when I'm free for a call.

[1] seriously, my time is just as valuable as yours. To me it's even more valuable.