Previously, Swash offered Ethereum for withdrawals but has since changed to offering only Gnosis Chain. There are several reasons for this, but primarily because Ethereum’s energy usage equals the consumption of around 721k US households, whereas Gnosis Chain equates to around only 2.1 US households.
As well as being greener, Gnosis Chain is also cheaper and more efficient, which means Swash can easily cover the cost of transactions on behalf of Swash users.