It is necessary to have a 'pos_check' gateway even though there is a 'cheque' gateway built into woocommerce. This is because the use cases are different. It is completely logical for the built in gateway to set orders to 'on-hold' as the check would have to be mailed in. For a POS, that is a very inconvenient way to handle it. A check will always be provided at the moment of the sale, therefore it should be marked as completed immediately.
Because of these differences, the built in gateway will never be changed, and most likely, neither will a filter be introduced into woocommerce to make this behavior tweakable.
It is necessary to have a 'pos_check' gateway even though there is a 'cheque' gateway built into woocommerce. This is because the use cases are different. It is completely logical for the built in gateway to set orders to 'on-hold' as the check would have to be mailed in. For a POS, that is a very inconvenient way to handle it. A check will always be provided at the moment of the sale, therefore it should be marked as completed immediately.
Because of these differences, the built in gateway will never be changed, and most likely, neither will a filter be introduced into woocommerce to make this behavior tweakable.