I hope the EU sues the shit out of MS some time for this "feature". Write protection is one of the few things Libreoffice can't handle well, and from my perspective, that is the entire reason they have it. Also, funny enough, Office 362, their own fucking product, also can't handle it. So you need a computer where you can install the desktop version, just to untick the fucking "write-protected" box and do your job.
In academic research, you often have to apply for money from funding agencies, using write-protected templates. If you don't use the exact template or if it looks distorted in some way, you're out (of consideration for the funding, and long-term out of your job).