While the word shape meme is a myth [1] there are some half truths to it.
It is known that mixed casing does disrupt reading [2], which gives some weight to the idea that the shapes of words and letters does affect reading.
For myself I know that my reading speed and comprehension suffers when reading title cased sentences. This leads me to always "fix" [3] documents I update or otherwise contribute to at work when others do it for headings, subheadings, headers and footers.
It is known that mixed casing does disrupt reading [2], which gives some weight to the idea that the shapes of words and letters does affect reading.
For myself I know that my reading speed and comprehension suffers when reading title cased sentences. This leads me to always "fix" [3] documents I update or otherwise contribute to at work when others do it for headings, subheadings, headers and footers.
[1] https://www.mrc-cbu.cam.ac.uk/people/
[2] https://pubmed.ncbi.nlm.nih.gov/9293635/
[3] I say "fix" because I know it's a generally acceptable formatting method when writing, I just don't like it.