In a singleplayer survival environment, which is where I play because I have no friends, spawning anything in that would otherwise deplete the world or heal the player would be cheating. Need stone? Go dig it yourself. Wants some bread? Grow some wheat. Need some cactus for a purely cosmetic reason that you super-duper secret swear never to use any other purpose. Do you have a cactus farm? Yes? Well... I can look away while you spawn a stack or two. You've got a sheep farm and want some white wool to build with? I'll just be over here crafting, I'll just make sure to "lose" some sheers.
On a multiplayer survival environment anything spawned in is cheating.
