For street use...the braided lines just look better.
Steel braided lines are used in racing because they do not flex or expand...unlike like the rubber lines which do expand under pressure. The harder the brakes are appiled, the more the expansion in the rubber lines. When racing...you are at max braking limits several times a lap. The steel braided lines give you a better feel for braking limits and are much more consistent in their feel and performance...with no mushiness.
For street riding...the little bit of flex or expansion in the rubber lines is really a non-issue. For street use...it's really just about looks.