Besides that, there are no windows...and in America those doors in the ground are easily opened and entered by the bad people.
You've got it wrong. Basements are mostly below the ground except for about 2+ feet or so, allowing for small windows close to ground level that provide natural light. Those are an easy entry point for criminals.
Metal basement doors otoh often haven't been opened in a long time and are fairly well-locked and stubborn. My father recently discovered that tree roots had pushed the concrete and metal so that the one door wouldn't open anymore and the other was mostly wedged in too. Also, once you open the outer metal doors, there might well be a second interior door to contend with. Often times those are nothing too substantial, but could be for the security conscious.
Much easier to kick in or jimmy a small window and then slither in than try to pry open a large noisy metal door. And since there are lots of low basement windows, usually one or more will be obscured by bushes providing cover, whereas the basement doors will usually be kept clear and visible.
Otherwise I think only old-fashioned and perhaps more rural basement doors are flat against the ground. More common, last 40+ years is to have raised slanted doors. I assume because they are easier to open, as you don't have to bend all the way down and then pull up, plus if anything thing lands or falls on such doors it slides off rather than accumulates and weighs on the doors. Sheds rain water better too.
Personally I favor incorporating the sump pump into my basement torture routine in order to obtain a more authentic feel.