It's a counter exemple extremely overused and a bit tongue in cheek but : try to see how long you can go without breathing, then ask yourself the same question again.
If you work out frequently, stopping that cold turkey is brutal also. Working out is unquestionably good for you. How hard it is to stop has nothing at all to do with how good it is for you. No comment on if it's good or not, but your comment has no bearing.