For what it's worth, the Dutch Central Bank argues that this is simply because it'd be easier to sell in London in a crisis situation. They've previously state

For what it's worth, the Dutch Central Bank argues that this is simply because it'd be easier to sell in London in a crisis situation. They've previously stated to be far more worried about the dependency on VISA and MasterCard than the gold reserves in the US. https://nos.nl/artikel/2560460-dnb-maakt-zich-zorgen-over-amerikaanse-invloed-op-pinbetalingen https://nos.nl/artikel/2560460-dnb-maakt-zich-zorgen-over-am...