I think it should be added, since it enables new gameplay options. For example, you can settle a city for the express purpose of helping you assault an enemy city, then raze that city once you're done. Like a siege camp IRL. Something Civ lacks as-is. It can also let you go all in on the on-growth yields. Build a new city, grow it fast, then raze it so you can do it again. Normally you will run out of space eventually. However this absolutely needs to have some kind of cost or restriction.