It is more difficult to make an analog circuit hold a voltage for any length of time. That is what an integrator does. Adding, subtracting (which is what differentiation does) multiplying and dividing can all be done easily with analog circuits.
But holding a charge is difficult. A capacitor can be used for very short time, but it "leaks", and looses charge over time. There are ways to compensate, but they are complicated and usually not easy to implement in a production environment.