Joey, Do You Like Video Games About Gladiators?
The arena. The roar of the crowd, the glory of bloody victory, the annoying fans that follow you around afterwards. Video game writers love the classical Roman Coliseum because it's an easy way to combine a narratively lucrative set-up (such as the many reasons you might want to win an arena tournament, besides cash) with what is essentially a simple-to-program gauntlet of opponents to fight.
Some games are based almost entirely around a central arena, or multiple arenas. Others will often use them in creative or entertaining ways, either attempting their own spin on it or simply making fun of the concept. Occasionally a game will place its toughest bosses in there for those players still aching for challenge after the story is complete. Here's but a few examples: