You can use the mass of the concentrator target as a thermal battery effectively, as the conversation of sunlight to electrical energy is not instantaneous like solar PV.
Indeed the advantage of your photovoltaic solution is versatility in the face of clouds and lower mechanical costs.
But the drawback is the larger panel area, higher panel cost and probably shorter panel lifetime.
Photovoltaic efficiency is about 20%, while even low-cost mirrors reflect 90% of the energy.
It really depends on the specific application and the answer does not seem so obvious to me.