The capacitance is also in series with effectively a zener diode, if you applied 10v to the gate of a fet via a high value resistor the voltage will quickly rise the vth (threshold voltage, the voltage at which the fet starts to turn on), then it will level out till the capacitance is charged, then finally reach close to the 10v i/p.
Fet gate driver ic's are designed to charge and discharge this capacitance as quickly as possible for switching applications, as while the fet is bewteen on and off off states its effectively a resistor and will dissipate energy as heat.