Earlier quoted context omitted.
Cross system / OS landscapes can make it nearly impossible without Obsidian Sync. It's okay for Android & Windows, but if you throw an iPad into the mix, you can't really find a local/cloud sync for them all. iOS especially has some limitations on how apps can access files, so your only options are iCloud or Obsidian Sync. For more info see here: https://help.obsidian.md/Getting+started/Sync+your+notes+acr...
This is untrue, I use iOS Working Copy connected to my git repo which contains my Obsidian vault. It's also on on my android pixel phone and I have it on my windows machine. Everything syncs just fine using a private github repo.
Of course obsidian is not open source so I can't guarantee their e2e sync service doesn't sneakily send the data to their servers, but it's still less risky than having it easily available to the company employees.