Yeah I'm a little confused too. The thing with windows is that you get what you pay for. It's ridiculous to think that there's some kind of window design that's magically available in Europe but not in the US. There are probably designs that are more common in different parts of the world, but it's absolutely not the case that if a homeowner wants to pay for it they can't get whatever they want in the US.
I have to think this post was made by someone who knows nothing about construction.
The idea is protection from crime. You can have the window tilted and thieves theoretically cannot climb in through that window, where a swinging or sliding window while open allows someone to climb in through it
Of course in practice they're less safe where they're popular as there is a tool, a hook, which allows someone breaking in to hook the handle, pull the tilted window shut, and open it again in swinging mode, allowing them in
My understanding is sliding windows are the easiest to secure as you can bolt lock them at any point of openness. My sliding windows have bolt points at closed and at 5cm open