Cryptocurrency isn’t currently supported within QuickFile I’m afraid. You would need to record this as it’s GBP equivalent for the time being.
There is an open feature request relating to BitCoin so you may wish to add your vote to that thread (below) - I appreciate it’s different from Ether, but it’s the length of the numbers that raises an issue, as most currencies support 2 decimal places, whereas Ether and BitCoin (and others) support considerably more. My colleague explains the issue better in the same thread: