I feel one of the main reasons is a few traces of nostalsia, a cup of continuity, and five table-spoons of aethestic expectations. Almost everytime I've seen CGI dino feathers rendered, it turns out really sloppy and makes them look like deformed paper-mache geese. Many people would probably cry how "the studios ruined everything" if they did give any of the dinosaurs feathers, unable to take them seriously as ravinous predators. But yeah, if it were any other movie I might raise an eyebrow to this, but this is JP-4 we're talking about. As others pointed out before, they're NOT really* dinosaurs but lab created chimeras with frog DNA used to fill in missing genetic sequences. Great pic by the way, XD!