Selective sync recreates the whole file structure on all devices. So you see the files, but they have no content, they are empty, they are just placeholders. If you decide you want a file or folder, you right click on it and select to sync it, too. So for sensitive files, as you said, maybe not so ideal.
But what you could do, for example if your folder structure looks like:
- PICS
+ Private
+ Public
Instead of adding the folder PICS to resilio, you add Private and Public individually, then you can only add Public at your work, and add both Private and Public on your private machines.