Not sure if tag-along questions are allowed but I'm also curious how citizenship was validated in order to obtain those benefits. There certainly were no ID cards or drivers licenses back in those days.

This always seemed slightly odd, given lower life expectancy back then? If you joined up at 18 and were granted citizenship at 43 after 25 years of what could be a dangerous career how long would you likely be able to enjoy it for?

Edit: -5 downvotes for asking an arguably misguided question. I'm not a historian and was curious. I was ontopic and not spamming or trolling. Friendly sub you all have here.

Was this benefit worth the military service? This sounds like a rather personal question, not sure you need to ask historians for that. Consider that auxillaries had different reasons for serving in the army, mostly to cover the basics - food, shelter. Citizenship was a bonus, I doubt many considered in the beginning of service, but I would imagine many thought about it after a decade or two.