The career growth is really amazing. I work at a unionized place that is required to fill positions internally before outside hires. When a senior employee retires from a top level position it will be filled by someone at the company. Typically someone in a mid level position. Then there’s a chain effect where now that mid level position is open that will go to entry level workers. The only outside hires tend to be for entry level jobs.
It’s great because when you talk to the senior staff, almost all of them started at the bottom and worked their way up. This gives them better knowledge of how the whole operation works since they’ve done the jobs below them, and also a little empathy!