Obviously there is more than one way to look at this, but 11 ounces is far from insignificant. 11 ounces here and 11 ounces there and pretty soon you are carrying 60-100 pounds of gear. If you really want/need to carry stuff there it might be worth it, but I don't personally find it that big of a plus and it therefore isn't worth the extra weight to me.

It makes a difference what size frame you have, but for me the rack top isn't very useful for carrying other stuff if I am using a handlebar bag. That may be less the case for others since I am on a smallish frame and like the bars very low. I do use a tiny front platform rack from Nashbar, but I only use it as a way to carry my handlebar bag. Weight is is actually reduced in that case since it weighs slightly less than the mounting bracket it replaced.