Many writers intentionally separate tooling to force workflows, even at the point of great inconvenience if it provides for an environment they feel is more conducive to writing. This is generally far more important than whether or not getting it into a format that editors can work with is extra effort or not.

Hemingway famously favoured pencils for his first draft and switched to typewriter for his second.

Gaiman and Stephen King uses pens for at least their first drafts. Gaiman expressly for the reason that he believes it force him to be more thoughtful and forces him to go back and rewrite the full book word for word rather than going back and forth to edit. King switched to pens after his car accident.

JK Rowling wrote Harry Potter with pen on loose sheaf paper.

Writing novels is intensely personal, to the point where writers will insist on specific brands of pens or specific models of typewriters. E.g. Danielle Steele has used 1946 Olympia's throughout her entire career.

i am probably the wrong person to respond because the reason i prefer a plain text editor is that that's what i have been using for all my work until now.

i am not yet there in the process, but i won't be using plain text/markdown just for the first draft.

when i get back that word documents with comments from the editor, i'll look at that like a read-only copy, and actually make the required edits in that same plain text editor.

while it may be easier to make edits right in place in the word document, it is easier (for me at least) to keep a history of changes with plain text documents.

otherwise i'd agree with you. if you are going to end up editing in word, may as well start with editing in word. for me the goal is to avoid using word/libreoffice at all.