I just assumed Rose was on work experience, hence her undefined role at UNIT. Did they reference how much time had passed for Rose, Colonel Ibrahim and Kate?
1. You get a pension for saving the world, but they do want you to work for it sometimes.
2. Doctor Bait. Put his friends in trouble, and he might show up, when all seems lost.
3. Unkillability, which is more a statement of how lucky they are, rather than how durable they are.
4. Time sensitivity. Traveling the TARDIS brands you with other worldlilness, where you might as well sometimes be a medium or a psychic in some situations, that a normal person wouldn't pick up on.
5. Future Knowledge. Elections, wars, plagues, technology. Just little things. I often wonder how Barbara and Ian Doomsday Prepped for the Dalek Invasion of 2157... Only to run head first into several beach heads in the early 21st century.
6. Actual human earthly transferable skills. Rose is a tailor who makes sex moppets for Japanese businessmen on ebay. There's bound to be an adventure eventually where ebay gains sentience, tries to dot and bubble everyone, and only Rose Nobel can save us.
7. Rose spies on the rest of her family. Write reports for the the intelligence community. "Grandad sat in his shed all day listening to Tommy Dorsey on vinyl again. Please pay me 4 thousand euros."
8. Prophecy. UNIT figures out that Rose is instrumental in some dire future events, and thinks it best to train her up with tech and kung fu, and be on hand when said dire future events happen, to get her out the other side alive.
9. She got the job on her own merits, and her position has nothing to do with the Doctor or charity.
10. She's another Timehead like River. %1 Timelord. Although she was not conceived on the TARDIS in the vortex, her mother's reproductive jellies were probably somewhat twisted by her exotic adventures, so Donna's special baby is also a magic baby, so UNIT has to monitor Rose and shoot her in the head if she goes bad. (Actually! This happened, I just forgot about it, because the Starbeast is a terrible episode. %40 of the story was about running away through adjoining attics like Bedknobs and Broomsticks became a weekly serial.)