Ex,
No it means what it says - your average candidate for finance, manufacturing - pick a sector - will not have had the exerience of making those sorts of decisions and the potential repercussions of getting them wrong. Just because you leave the mob, it doesn't mean that you don't take the experience of making those decisions with you. And should you leave and then decided to jettison all the skills you have picked up, then that's your choice but probably not a good one.
Compared to the average civi st newby Joe's age, whose biggest worry is getting the bosses tea order right or maybe passing a series of accountancy exams (which can be retaken without anyone dying if failed), the average service person will pick up experience involving far far harsher consequences if they fail. And that is most definitely a valuable experience for the future. If nothing else, it allows you to put a lot of seemingly important but in the end trivial mistakes into perspective.