@Jaegrqualm
It has about as much context as American dollars do, to people who use neither. Better to keep it as the original than leave me having to remind myself "no, wait, the other dollars" and have to convert.
Besides, even for those who are familiar with American dollars, people who read manga gain a grasp of what the yen is worth anyway.
Still, it's better than translators who convert metric into US Customary. At least the "30 centimeters tall" was intelligible.