On one hand (heh) there's apparently evidence to suggest that handwriting activates parts of the brain which aren't typically activated by just typing something out. I can see how that would be the case and why it could sometimes be useful.
On the other, the idea of carrying a little notebook around to jot things down when I have a phone in my pocket, or using a fountain pen for longform text (trust me it would actually help you avoid hand cramps, aside from being less wasteful) all comes across as... intentionally inefficient? I struggle to see intentional inefficiency as anything but pretension. Like it's all just fetishizing living a more analogue life.
It actually makes the techbro in me think there's something to companies like Supernote and Boox and ReMarkable making e-ink tables that exist mainly so that what you do choose to write by hand can be digitized, stored and made searchable.
I suppose that's actually exactly why people tend to journal in physical notebooks? Because what you put down in there will just disappear unless you crack open that notebook again.
...Meanwhile I'm pretty sure a lot of people feel that writing things by hand gets their creative juices flowing. That's sort of interesting to me, because personally, by the time I'm finished writing a single sentence whatever I was thinking about is halfway gone. If I don't get it down real quick my thoughts will drift to something else entirely, so when I had to handwrite essays in primary school I'd get completely stuck in a way I never do just typing things.
TL;DR someone who's bad at empathy talks about handwriting as if everyone else experiences the world exactly the same way, please knock him off of his stupid pedestal