No this isn’t about who would win in a fight between Superman and Goku. Specifically this is about a particular mainstream Japanese hero character I see over and over again in Shonen action based Anime / Manga and how it compares to mainstream American super heroes. Of course I don’t mean to say there aren’t characters on both sides that break the mold, only that the type I describe seems interestingly prevalent in modern mainstream media.
For me, the biggest difference is that Japanese super powers are based around a growth mindset. The hero must train hard to unlock his hidden potential. Even if he is the chosen one of some kind or come from another planet, it doesn’t come for free, it takes hard work. Most American super heroes were born with their powers or gained it all at once through some happenstance beyond their control. They will usually go through an awkward period of learning how their powers work, but it will be more about discovery than training.