Re: Seems like a losing battle, and there's an elephant in the room
First of all, Libreoffice has the same option to use Microsoft XML or Opendocument XML, so I can't see what the big play is surrounding file formats.
The big play around file format is how well they are supported and how well the application interprets that file format and displays it. OO.o and Libreoffice provide support for Open XML, but it works in a different way to Microsoft Office and it can't display the file "cleanly", there are always minor differences between them on how things are displayed, so the formatting goes to pot.
I've had presentation in PowerPoint that were displayed in OO.o or LO and the lines point to different objects on the page and the objects have moved as well! Word documents, the page formatting goes to pot, the ToC will say a section starts on page 12, which it does in Word, but due to formatting issues in LO, it will be on page 13 or 14 - the higher the page number the bigger the difference to where the ToC says things were and where they actually are.
(The same goes in the other direction, of course.)
If you are sharing documents with people, you really need to be on the same version of the same program - even version differences can cause formatting issues when swapping back and forth. I used Linux for a long time as my main workstation and worked with LO, but for documents that I had to share with clients (where I had to provide the original and not a PDF), I always had a Windows machine in the corner to check the formatting, before it went out. At some point, I was spending so much time correcting the formatting that I gave up and switched back to Windows and MS Office for document generation, because it saved time and I wasn't going to get a large, multi-thousand seat, client to switch from MS Office to LO, just because I wanted to use that.