You grew up with them, of course you think they're fine.
People here who grew up with adapters to plug the iron into the light fitting thought they were fine too.
Doesn't mean either of you are right.
The NEMA 1-15/5-15 are the two most common in a domestic situation. They come out very easily with a light tug on the wire - encouraging people to unplug things that way, damaging the cable.
In use, the 1-15 tends to sit at an angle, exposing live contacts to a small finger or teaspoon.
They often arc while doing so which damages the socket contacts.
Lots of real users smash off the earth/ground pin of the NEMA 5-15, defeating the only safety device you have.
The reason for the relatively low electric shock death rate over there is the low voltage. Unfortunately you pay for this with a higher rate of deaths due to electrical fires.
Some states require arc-fault detector trips in an attempt to reduce that. Personally, I think those are daft due to the false-positive rate. A trip in your electrical cabinet that often pops when you unplug something is pretty useless.
Also, I can draw 3kW from my 13A plug, you only get 1.8kW.
My kettle boils faster than yours, this is important for tea.