Because the component inputs on the mini are poor.So why do people mod their Component cables to VGA and combine the signal to RGB then?
For the record I got the Extron+Sync Strike working perfectly, all it took was to use an external PSU with it. I still see the discoloured band on the left of the screen sometimes, so I guess it's just something some PS2s do.
Also, I've been extensively testing an affordable transcoder (Component to VGA) and been pleased with the results so far, will do a full write up soon. It's RGBHV output though so you still need to sync combine it to use it on the mini.