Shadowing is very important for jobs where the outcome of failure is potentially harmful or costly. Biological research is done almost exclusively through an apprenticeship-like training system, and part of that system is that you shadow a mentor when you start. (You’ll also continue to work closely with your mentor so that they can continue to supervise you personally for a long while before you’re allowed to work on your own)

My understanding is that hospital or medical work is pretty similar in that regard

I can’t speak for all jobs, but shadowing is an effective tool and I’d be shocked if it isn’t pretty commonly applied. Not always in an apprenticeship sort of way to learn from scratch, but certainly to better understand the nuances of a role.