Re: Personally ...
If you are an author you don't need to care about layout - that's what you have publishers, editors and cover designers for.
It's like saying a composer should use a mixing desk because they need to know what level of compression will be used when they music is played on Radio3.
No, it's more like saying that a composer should not compose at the piano because he's there to write the music not to play it.
It overlooks the fact that while some composers may be happy to write straight to manuscript paper without playing or hearing the work as they go, others will want to play passages through, listen to them, and maybe solicit the opinions of their friends and families; and that some composers go on to perform their works in public themselves.
Just as some writers write only text that is later edited, laid out, and published in house style by a publisher while others want to see and review their text laid out (not necessarily in its final form) and ohers again may be publishing their own work and have to perform the tasks of writer, editor, and typesetter themselves.
There's more than one way skin a cat!
No animals were harmed in the production of this comment.