What are the drawbacks of simple pendulum?

The drawbacks of simple pendulum are as follows:
a) The simple pendulum can’t have a weightless, heavy point mass bob with inextensible string as we assumed.
b) The motion of the bob is not strictly linear.
c) The resistance and buoyancy of air affects the motion of the bob which is supposed to be negligible.
d) The amplitude of vibration of the bob may be large.