US style plugs and derivatives (and Australian, Japanese, Brazilian, etc) - all invented by Hubbell - are "good enough".

Are they objectively good? No. Do they regularly fail, cause fires, or shock people? No.

Even my kids when young understood how to grip the plug without touching the metal contacts and to this day still have not been shocked. In theory can something fall and hit the pins just right to cause a short? Sure. You could also get struck by lightning. In practice it just doesn't happen very often.

For the US/North American NEMA style there are some improvements and some clever things about them. Modern receptacles have shutter doors that stop you from putting anything into the holes unless the ground pin or neutral pin unlocks it first. Many plugs also cover the rear part of the hot/neutral with plastic so if the plug is not fully inserted there is no exposed metal.

The plugs also prevent mixing voltage and amperage. The typical two vertical blades (5-15) are for 15 amp circuits. 20 amp circuits (5-20) have one horizontal + one vertical blade. The receptacle has a T shaped slot to match - that way you can plug a low-amp device into a high-amp circuit but not the reverse.

Similarly the 240v version of this plug (6-15/6-20) has the same property: 15amp and 20amp versions. The 15 amp is two horizontal blades. The 20 amp is one horizontal + 1 vertical but swapped places compared to the 120v version. I do wish more builders installed the 240v receptacles in kitchens in the US. There is no technical reason we can't have higher power kettles and whatnot. If code required these in garages and kitchens more appliances would be available for them.

(I find it insane that Brazil continues to be dual exclusive voltage; all of North America is dual concurrent voltage. Every home/office has 120v and 240v available. In Brazil it depends on what state/city you live in - some get 120v, some get 240v. Even worse they use the same standard plug design for both so you'd better hope the plug is the right color or has the right sticker. And you can't be sure you can take electrical appliances from one city to the next! At least they should have adopted different plugs for different voltages.)

The huge advantage of these plugs is compatibility. We already have them. The cost to change designs is massive. The benefit extremely small. It just isn't worth doing.

Note: The 240v NEMA plugs I am referencing are not "dryer plugs" which are physically much* larger and designed for much higher amp loads in the 30-60 range. The 6-15/6-20 are literally identical to the standard 120v plugs but with different blade orientations. They were designed to support 240v appliances in everyday use since all of North America is dual voltage. In practice 240v is only ever used for large appliances like ovens so the 6 series doesn't get much use which is a bit of a shame.

Museum of Plugs and Sockets