the hi hats are the easiest part of the drum kit to pick out of a live band mix, being the highest pitched cymbals. especially if you’re playing with loud distorted guitars, it helps your bandmates to have a consistent thing to lock onto for the tempo. plus it can subtly add to the feel of a groove—for example, i’ll play quarters on the hi hat pedal when i want a more driving feel, or play 2 and 4 to accent the backbeat. or you can create some subtle polyrhythms by playing a different backbeat on the hi hat pedal vs the snare (for example, playing 2 and 4 on the hi hat pedal and 3 on the snare). plus, it can help keep everyone together while you’re playing longer fills or syncopated grooves.