I can see where both polarbear and dude are coming from with this. I am one of those whose hands are much harder to control when handwriting than typing, handwriting IS a barrier to spelling for me. Conversely I see the damage done to my kids through the "anything goes" approach to writing in early grades here "because we just want them to write SOMETHING".
My handwriting problem is genetic, I have a connective tissue disorder, all three of my kids have it, due to LDs my eldest didn't start meaningfully writing until about 3rd grade, when her school were also finally heavily focused on handwriting. Her handwriting is ok. Second child was encouraged to do the "anything goes" from 3.5-4, and she also loved to write, she wrote before she could read, she's required intensive therapy to correct her handwriting, it's kind of worked, she's made astonishing progress with her output, but her grip is still a disaster and she's probably going to need keyboard use quite young. Youngest child is 3.5, despite my warnings about her hands her Monti preschool have gently taught her the most beautiful grip and she's learning to write correctly from the start.
I don't yet know if my eldest will cope with producing volumes of writing at speed without pain, or if my youngest will continue to develop well with handwriting, I don't know if their hand problems will be equal or different in adulthood. But right now I am deeply resentful of the way middle child's preschool and early teachers approached handwriting because I suspect she's going to have the worst outcome despite possibly not having any greater physical disability.
It's hard for me to judge how handwriting and spelling intersects for my kids as the eldest is severely dyslexic and the middle child is not AND has 20 points on the eldest in verbal IQ, and way more than that in WMI, which shows. The youngest cant read so I can hardly judge her spelling.