Congrats to your new MBP
Filevault is a pretty secure way to have your hard disk/SSD encrypted. If your want to go one step further, google & download a program for encrypting individual files. There are plenty of it...
Filevault can also be used to create an encrypted USB stick, which you can use to store all confidential data. When travelling, you can "clean" your Mac and have the stick not in your laptop bag but somewhere else. I would even advise to have all sensitive data e.g. on your company´s server and travel with a clean device only, downloading data via a VPN connection when arrived at your destination. There are countries in this world, where it can happen that your laptop gets conficated at immigration and returned to you some hours later....we can guess what happened in between... So clean your Mac when travelling to destinations when you are concerned of industry espionage
If you are concerned that your Mac gets stolen, install "Find my Mac", it will locate your device when it is switched on and connected to the internet.
A invisible marker has the disadvantage that it is invisible. So, it only helps when found and it has to be clearly identify it as yours, but first it has to be found, and the marker doesn´t help with it.
