The high prevalence of NEMA 5-20R receptacles (outlets) (with the T shaped hole on one side) makes me wonder why there aren't more consumer appliances with a NEMA 5-20P plug. The 5-20P plug may draw 20 amps instead of 15 of the common 5-15P plug, or, multiplying by 120 volts, 2400 watts instead of 1800 watts.
More wattage could be especially useful for electric kettles, computer power supplies, hair dryers, space heaters, air conditioners.
Product packaging can prominently label that it has a 5-20P plug so requires a 5-20R outlet. People who do sketchy things like use a plug adapter to plug a 5-20P plug into a 5-15R outlet will get what they deserve, probably a tripped circuit breaker.
One could draw even more power using a 208V/240V outlet and plug, but that's usually only present in at most one place in the home, for the electric clothes dryer.