One button toy
When people are buying microwave ovens, they don’t want the clunky one with fancy buttons and the spinning glass plate.
They don’t have enough time to be occupied by multiple buttons.
Same stories with a love vibrator, consumers want one click to get orgasm instead of falling victim to completed operation.
Fancy appearance is just icing on the cake.
They want to be sure they are paying for a handy toy instead of spending much time and get bored on learning how it works.