[jsheard]

It depends on the application, a short-lived script may complete all of its work before the GC interrupts it, but something that runs continuously can't afford to generate much if any garbage in its main loop because it will inevitably pile up and eventually cause a huge stall when the GC decides that enough is enough. It's especially critical for animated or interactive applications like games, because with those the stall will manifest as the application freezing completely until the GC is finished.