Danaher says:

The strangle is the ultimate weapon in Jiu jitsu: Jiu jitsu is the art and science of control that leads to submission. Within the realm of submissions you have two main choices – joint locks and strangles. Both are essential knowledge, both are extremely effective – but if you are ever given a choice – go with the strangle. Strangles take the element of CHOICE out of submission. Whenever you attack a joint your opponent has a choice of whether to submit or not. The higher the stakes – the more likely the choice will be no – I will not submit- and the match will continue. With strangles, their choice becomes irrelevant. If the choice to submit, the match is over. If they choose not to submit – they pass out and the match is over. The choice has no effect on the outcome. In a truly tough match with an opponent who is prepared to reckless with their physical health and safety – The strangle is truly the grapplers equivalent of a knock out punch, while the joint lock is perhaps closer to the notion of a body blow – it causes damage that degrades your opponents ability to fight and thus takes you closer to victory but will not always provide a decisive finish. LEARN YOUR STRANGLES! In your toughest matches they will be your most trustworthy weapon.