I have to design a bio potential measurement system: 

 - AD converter and the connecting digital / software part
 - an analog amplifier stage: basically a regular ECG amplifier composed
   of discrete instrumentation amplifier

Googling around I see that the instrumentation amplifier's reference input is driven by a miller integrator feedback.

My question is:
what is the purpose / advantage of this miller integrator feedback?

I think, remove DC component can be easy in software side, hardware cost, size, complexity and PCB design can increase dramatically.