Multitasking doesn't exist. Distractions do. Deciding which is a task and which is a distraction is the only way to get anything done.

We treat both external documentation and internal documentation as a deliverable in a sprint. Working on documentation iteratively has the same benefits as working on code the same way.

What Agile is against is large up front specifications, not documentation per se.

This is painfully relatable... Marketing and sales teams don't seem to mind much but as a developer I once had to quit a job because of this.

I actually worked in sales and trust me, we DO mind the noise. Imagine trying to talk to a client on the phone when you can barely hear yourself.

Also gives me a pretty poor impression when I hear other sales people shouting over whoever I'm talking to. Feels like they are in some kinda boiler room selling me vapourware.