Blow's comments on Rust were briefly touched on in the epic AMA with kyrenn from Chucklefish games (Starbound, Stardew Valley) who are making their next game with Rust.
Was Jon Blow correct in saying that enforcing memory safety is a wash for games development?
It's Jonathan Blow, so I'm inclined to say that you should take whatever he says and weigh that much higher than whatever I say. That being said, I really really really disagree.
The problem is not that you can write a bug, and then you run your game and your game crashes. The problem is not that you can write a bug, and then if you give your game ridiculous input it can crash. The problem is that you can write a bug, and 99.999% of the time your game works fine, and .001% of the time your game does something wrong and you don't know why. The problem is that your game works fine under error condition A, unless some other error B happens, and then your players lose their save because errors A and B are both safe in isolation, but if A happens and then B happens, that causes UB.
I remember at least 5 major instances where there were multiple programmers in the office, pouring over some minutia in the C++ standardese, trying to figure out if some corner of a corner case of C++ was UB or not. Can anybody really keep the default / zero / value initialization rules in their head? We thought we knew C++14 backwards and forwards and still managed to have uninitialized value bugs, and they're awful because depending on the situation they will mostly work. I can count three or four times in Starbound's history where I was bitten by just the std::unordered_map iterator invalidation rules, that one's awful because you have to trigger a rehash often times in order to trigger the bug. I hear people say things to the effect that C++17 "more or less" solves the safety issues, "just use modern C++!", but I promise we were way ahead on that front and that was not our experience at all. We basically used C++17 before there was a C++17 (we had our own Maybe, Variant, Either etc), and UB was still always lurking right there ready to bite. It was HARD to get right.
I didn't really mean for this to turn into a C++ bash rant, and I really don't want to be militant about it. It's possible that you don't have these problems in C++, maybe you're a better programmer than me? Seriously, it's possible I'm just not good enough. Certainly maybe Jonathan Blow is better than me!