I attended a talk by Richard Garfield, the game designer behind Magic: The Gathering. He made a point that adding randomness to a game can be a way to give it that property of "easy to learn, hard to master", and in turn make it easier for a community to grow around the game. When you add randomness, it becomes possible for novices to sometimes beat more experienced players through sheer luck. Contrast that with e.g. chess, where it doesn't take much skill difference before the most skilled player is almost certain to win. So randomness makes it easier for newcomers to get the occasional win, to keep them motivated while learning. But at the same time, randomness can make it harder to master, because the cause-effect-relationship between good decisions and good outcomes becomes blurred, like the article points out, defeating the trivial "reward function" we usually use for evaluating our performance. It takes a lot of discipline to say "I won, but it was luck, because I actually misplayed" and learn from that. And on top of that, high level play will become a game of analyzing and estimating probabilities, minimizing or maximizing variability depending on the strength of your position, basically embracing randomness as a gameplay element to be understood and sometimes even manipulated, despite being so intangible compared to most other gameplay elements. So used the right way, adding randomness to a game can both lower the barrier of entry, and raise the skill ceiling at the same time.