Panda3d Collisions made simple

#* to have collsions, the engine uses the model geometriy but to optimize the execution time is common practice to use simplified geometries - in our heart egg file we have provided a simple sphere to use for this purpose (look into he blender source to know what I mean) and so we'll gather it from there...
c = heartTrigger.find("**/collider")

Why is the method faster?

JB