Generally these computer systems do access control, patient charting, intake management and most other critical functions, just like the rest of the world.
Blood banks and controlled medicines are likely gated behind access controlled doors, and without either it could cause major impacts to the ability to save lives
You really don’t as long as you’re leaving the OS mostly standard. I’m a fairly high level power user of windows and I don’t think I use any of the 3 outside of development work.