Having a U.S. as well as a Swedish (EU) passport means i have millions of additional job opportunities (and many from countries where salaries are much higher and 4-6 weeks of paid vacation) and can legally live and work in numerous countries. And there are places where U.S. passports are not normally excepted ex. cuba. Sure there are work arounds but much easier to go in and out on a passport that is accepted.
And in this day and age, there some countries where i will be able to get out of a beheading a hell of a lot easier by showing my Swedish passport than my U.S. passport.