There’s just sooo much wiggle room in prose — even smart, sharp prose. More than enough for you to fill in some blanks and imagine the characters as you want them to be. Images and sounds are different; there’s still wiggle room, of course, but not nearly as much.
What’s interesting, though, is that wiggle room isn’t always a bad thing: I found myself connecting with the wounded soldiers a lot more in the written stories. The other-ness of their gruesome injuries and their accents in the Flash pieces only made them seem more distant.