Maybe the death sentence for terrorists will make a martyr out of them but there are plenty of other ways that crazy people become radicalised, so it may not make a huge difference overall.
Weighed against the cost of keeping these scum for decades in our overcrowded prisons, with our hard-earned taxes, I would advocate giving them their expected paradise asap. 72 virgins or another misinterpretation - a 72 year old virgin?