Imagine for a moment that an invention you created saved the lives of a thousand US Soldiers. Imagine watching the cutting edge of technology, devices straight from a James Bond or science fiction movie, in action because of you. If these things excite you, then you might find it a glorious job.
Every missile ever developed, every jet, every piece of stealth technology or satellite tracking equipment was all born within the minds of Defense Engineers. Glory is definitely one of the perks.