Thermal cracking is expensive and inefficient (i.e., cost:benefit ratio is too high). This is the result of the great amounts of heat energy required to continually perform this process.
On the other hand, catalytic cracking is significantly more efficient and less costly due to the presence of a catalyst, zeolite, which lowers the activation energy of the cracking process to increase it's reaction rate. As such, less heat energy can be used which saves capital.
______
Enhancing this answer requires the inclusion of equations for comparison and a brief analysis on consistency of the output of each cracking process.
