I imagine that pitting LLMs against computer games is itself an enjoyable activity.

Generally speaking, people play games for fun, and I suspect that will continue. Even if an LLM can beat all humans at computer games, it doesn't matter. We will continue to enjoy playing them. Computers, pre-LLM, could already out-play humans in many cases.

Other activities mentioned -- writing, art, coding, etc. -- can indeed be fun, but they are also activities that people have been paid to do. It seems that there is incentive to create LLMs that can do an at least adequate job of these tasks for less money than humans are paid, so that that money is rerouted to LLM companies instead of human workers. I imagine humans will continue to write, create art, and even code, without any financial incentive, though probably less.

(I personally remain unpersuaded that LLMs will do away with paid creative work altogether, but there's clearly a lot of interest in trying to maximize what LLMs can do.)