The standard concept of such non-existent armor is that it can help to distract one’s opponent. But it came to me that there is a second possible reason for wearing next-to-nothing into battle.
It’s a concept I return to often. It came to me while watching some silly Schwarzenegger movie from long ago where some future minicar filled with foam on impact for safety. I realized then that the whole concept is antithetical to preventing accidents. The less consequence, the less incentive NOT to crash. The real solution to prevent accidents is to have a spring-loaded steel spike loaded inside the steering wheel which will be released upon impact. THAT would help prevent accidents, I guarantee!
So perhaps minimal armor would actually make for better motivation to win!