It's not necessary for LibreOffice to fully replicate every nuance of MS Office to be valuable to people who aren't just those who "would be Linux users anyhow."

Especially for the light users of MS Office, which are the vast majority. They just need something to create Aunt Bobbie's birthday invitation, and they won't care at all whether that thing is MS Office or LibreOffice.

As an anecdote, I'm the IT person at my job. I quietly removed MS Office from a shared PC used by dozens of people. I installed LibreOffice instead, and selected the ribbon UI option. Months later now, and literally nobody has complained or even remarked on it, despite using it every day for their document work. There has not yet been a single instance of anyone contacting me for tech support about it.