Super chlorinating with a cell may not reach shock levels of FC. If your cell was oversized for your pool it might be able to. But it might not. That setting usually just runs the cell at 100% instead of cycling it on/off.

And you are correct, it can reduce the life-cycle of the cell.

If your water is properly balanced and you need to actually shock your pool, then I recommend 12% liquid chlorine for getting the FC levels to where you want them to be. There are no extra additives or chemicals in liquid pool chlorine, just Cl. You can use regular household chlorine (choose unscented, no additives, etc) too. You'll just need twice as much by volume.