Perhaps the most common reason is data recovery. Many players have folders on old hard drives containing profiles from 2013. When they try to copy these files to a modern installation of ETS2 (which might be version 1.50+), the game crashes. Understanding how to manipulate save game files allows these players to potentially salvage their old progress, or at least view their old trucks one last time.
The biggest challenge
: Experience the original physics and truck models as they were in 2013. How to Install a 1.1.1 Save File euro truck simulator 2 1.1 1 save game