It's not best choice, it's a choice that is appropriate in some (quite restricted) setting where you don't really care if the program runs out of memory or paus

It's not best choice, it's a choice that is appropriate in some (quite restricted) setting where you don't really care if the program runs out of memory or pauses for a minute on an unexpected input. In many other settings having a inexact (or even obviously incorrect) result is better then stalling the whole system.