GC latencies doesn't bother them, because they put large efforts into ensuring there is not garbage to collect. Tricks normally reserved for hard real time embedded systems like allocating all memory buffers at startup time.

GC is very useful for programs that don't have any form of real time - but games are real time and thus you need to be careful to ensure that the worst case of the garbage collector doesn't harm you. Reference counted garbage collection gives you this easier than the other means. Note that I said worst case - the average case of garbage collection is better in most garbage collected languages.