Most drummers cross their arms when playing because it allows them to keep the rhythm on the hi-hat with their dominant hand. The vast majority of hi-hat stands that come with new drum kits are the standard fixed kind, which makes it difficult for drummers to change their position. Open-handed drumming is an alternative to this.
Not all drummers cross their arms when playing (Open Handed Drumming)
Open-handed drumming is a very valid alternative that doesn’t require the drummer to cross hands and the approach has quite a lot of benefits.
Open-handed drumming is great as a drummer’s primary technique, while it also serves as a great exercise to help drummers become more ambidextrous and develop more independence behind the drums. Left-handed drummers may also find open-handed drumming easier to play if they need to play on a right-handed kit configuration (and vice versa).
To play in this method comfortably, it can be beneficial to lower the height of your hi-hat a little.
Remote hi-hat pedals are a good alternative
Traditionally, hi-hat pedals were fixed and placed to the left of the drummer. The weaker foot was used for this as it was preferable for the drummer’s dominant foot to control the bass pedal. However, there are now remote hi-hat pedals available that are controlled via a wire rather than a fixed piece of metal, which means that the drummer can place their hi-hat anywhere around the kit that they want.
Drummers cross their arms as it makes it easier for them to keep the rhythm on the hi-hat with their dominant hand. For right-handed drummers, the hi-hat pedal is generally placed on the left so that the drummer can adjust the hi-hat pedal with their left foot. Open-handed drumming is an alternative approach to this.