I dont know gymnastics so I can't tell what's impressive or not. But I'll defer to the experts
Yurchenko refers to how she entered the vault. She starts with a round off (like a running cartwheel), her feet hit the spring board and essentially does a back handspring off of the vault table. After that you can do multiple skills. The fact she is in the pike position (her body is shaped like a V, like she’s doing toe touches) which is one of the more difficult positions... and the fact that she does TWO flips in this piked position makes it even more ridiculous.
You generally see a single pike, or maybe a double tuck (backflip with your knees pulled into your chest), which is easier than a double pike.