What is the purpose of an aftermarket bumpsteer kit

when installing mm k-member, coil overs, a-arms. I installed everything, but didnt do the bumpsteer, I just left the old one in there. Here are some pictures of how it looks, I dont understand why they say its required to get an aftermarket bumpsteer kit. Can you show me anything that is wrong with the way these line up or anything at all, I dont really know what bumpsteer kit does, or how its any different from the stock one.

http://i264.photobucket.com/albums/ii192/dankushead/bumpsteer4.jpg

http://i264.photobucket.com/albums/ii192/dankushead/bumpsteer3.jpg

http://i264.photobucket.com/albums/ii192/dankushead/bumpsteer2.jpg

http://i264.photobucket.com/albums/ii192/dankushead/bumpsteer1.jpg