One name for you...
He is considered one of the most influential doctors of modern physics. He was such a poor writer that he wrote drafts for writing letters to his friends. He dictated his dissertation to his mother to write down and had an assistant do most of his writing for him. He was also a genius and a recipient of the Nobel Peace Prize.
I do think that spelling is important, not because of proof of intelligence, but the perception of intelligence. It has less impact today because of electronic spell check, but if someone is looking at you, just on paper, this is going to be one of the most important factors. TBH, there are some posts online that I almost cannot understand or even get through because of poor spelling and grammar.
Also, I work in a library, and it seems that there is a LOT of handwriting happening in this environment... and honestly, patrons do not want librarians that can't spell. It kind of ruins the confidence that we belong there and are a valid informational resource, IYKWIM. I think spelling and orthography are still very important and I'd try to find a good way to help your dd learn to spell better. JMO.