Not being able to prove that text is human written is going to become a more and more severe issue going forward into the future. I don't think people have properly understood how serious it is. The simplest and most egregious example is fiction writing. In a future where AI can write fiction that is indistinguishable from human fiction, AI will always be able to output content faster and in greater volume than human writers. You will not be able to tell if a new novel you are enjoying is human written or AI written. I guess some people won't care, but for me personally, the idea of unknowingly ingesting fiction that's being soullessly pumped out by a machine makes me feel kind of sick.