Hey there. I wrote the Jai Primer. Ideas there are my best interpretation of Blows ideas, which I generally agree with, but bear in mind they&#x27;re not his.<p>To quote Joe Armstrong: You wanted a banana but you got the gorilla holding the banana and the whole jungle. You wanted a way to delete memory automatically, which sounds great but in practice most language&#x27;s approaches to solving this problem come with a host of other problems that at scale make the given solution not worth it. RAII solves a big problem but it introduces a bunch of tiny problems like big mysterious constructors that implicitly do a lot of work and deconstructors that don&#x27;t map to any particular line of code other than an ending brace. It&#x27;s tough to examine in a debugger, it&#x27;s tougher to reason about when it gets to nontrivial scale, etc etc. But human brains naturally weight a lot of small pains to be less bad than one big pain, so the solution looks legit.<p>Polymorphism is a way of modeling the world that runs along the lines of the categorizations that people tend to make, so it feels natural to create deep class hierarchies. But in practice it doesn&#x27;t match the problem that you need to solve when you make games - you have data in state A and you need to get it into state B. Example: to do a physics integration on each simulated body, the CPU wants to do a for loop over a list of position vectors. But those vectors have been scattered all over memory by the class hierarchy. So that&#x27;s one problem, you also get problems like needing RTTI and casting and yadeya. Class structures have largely fallen out of vogue in game development in favor of component systems, which is a pretty good step forward.