Whenever you transfer your $DRIP from one wallet to another it incurs a 10% transfer tax. In order to minimize the tax implications when paying bills or off-ramping with Spritz, we swap your $DRIP with $BNB first so that it only incurs that transfer tax once.
The reason we swap your $DRIP for $BNB is because the DRIP network has its own liquidity pool called the Drip Fountain, which is only for transfers between $BNB and $DRIP.