Should a dishwasher be plugged in or be hardwired?

dishwasher

a smart person would plug it in

Sorry but ONLY a portable Dish washer should/can be plugged in. the ampcity demands of a built in is higher, ( due to larger heating coil in built ins) ,you need to hard wire a built in due to fact that very few plugs are rated ot 20 amps 99 % are 15 amps and so are wires leading to plugs, too often they are 14 awg as opposed to correct 12 awg for a built in.