CCS is too expensive. It will substantially increase the cost of building coal plants (perhaps a near doubling of plant cost, according to the US Department of Energy) and therefore increase the cost of electricity also. The energy required to remove CO2 from the coal plant stream is also substantial and would consume up to 40% of the energy used by the plant.
Thus, coal plants fitted with CCS would require more fossil fuel inputs, and the prices of these inputs can only increase as time goes on and carbon is more fully costed.
Therefore, CCS works to make our energy supply more expensive and more wasteful as we go on and commits us to further dependance on coal.