The fiverr card at a cash machine dollars or pounds

[in2town]

Hi, when I use my fiverr card in a cash machine in the UK, it asks me if I want to withdraw money in the pound sterling rate or the dollar rate. Now I always choose the pound sterling but I am not sure if this is right or not. Can anyone who uses this card in the UK let me know what would be the better choice and why it makes a difference.