Yes, essential. I like to do it in an electronic mindmap, so in order to have it always visible, I needed to attach an extra screen where it's always visible.
"Mental effort" to get on the task that needs to be done is a different matter. I still needed to push through the pain to star. That got much better with treatment.
Like the whiteboard though; not as easy to shift things around and make changes, but advantages might outweigh that.
Wow, so different for everybody! For me, it went from the feeling of giving myself a cigarette burn to "eager to start".