Nicotine isn’t “meant” for anything. It’s a side product from a plant that works as a form of protection.
There is no healthy was to use it, but that’s true for almost everything in the world. There are responsible ways to use it, and most drugs should be legal to allow for this. If they’re illegal they’re still going to be purchased and used, but they’re not going to go through regulations that could prevent harm from factors that can be controlled for.