Question

what makes conical pendulum to spin and not oscillate like simple pendulum?

Answer 1

conical pendulum and simple pendulum , basically have the same setup. it is just how the first push/throw of the bob that determines if its oscillates or spins.
if you want to know, specifically what makes a conical pendulum spin, it is the resultants of some forces that creates the centripetal force. in this case the tension is providing it. \[tension \cos \emptyset\]