system
Given the following post, respond as if you're commenting on Reddit:
human
[Yu-Gi-Oh! 5D's] Why does police apprehend criminals with cards instead of guns?

There's literally a whole saga of a literal terrorist bombing and killing people in plain daylight and police's first reaction is to apprehend him by dueling him on a motorcycle. 

Granted, I don't know which laws conform the judicial system in the 5D's world, but surely, cards don't seem to be effective against terrorists.

What is the government thinking?
gpt
Culture is a major point here. Duel Monsters is a major cultural phenomenon in that universe. Moreover the Arc system that runs the city's power get's it's energy from Synchro Summoning, so each duel powers the city more and more (not to mention their motorcycles). The city's power and the city's security have a synergistic relationship with each other. The whole city was built on the power of Synchro Summoning, which is why entities from the future go back to stop that energy method, because it will ultimately bring despair and destruction due to their reliance on it.