That is exactly parent's point: a fountain pen makes sense for long-form constant writing, but not for short burst, sporadic note-taking.

No, that was just the first premise, the point was "you're better off typing it". They were implying that a fountain pen is a waste because it's only useful in situation you should be avoiding.

I think the parent you your post is a very valid criticism when paired with this sibling: https://news.ycombinator.com/item?id=6407094

To be exact, he started with the Baroque Cycle (http://www.ericaustinlee.com/2008/10/neal-stephensons-writin...).

He did? So what.