Not sure of the etiquette here, but I've modified this workflow to handle Bitcoin as well.
It's my first time ever writing Ruby, or for Alfred, so please bear with me if I'm not following best practices, and Jin5354 - if you wish to incorporate any of this into your existing code base (or improve upon it), by all means please feel free.
The only files that have been altered are BTC.png has been added to the flags directory, and convert.rb has been modified. However, rather than posting only those files and expecting people to take it apart and put it back together, I'll just post the modded workflow. It seems the board won't accept this file type as an attachment, so I just threw it on a file hosting service: https://nofile.io/f/2Orgj7NKZ7z/Currency.Convert.v1.4.btcmod.alfredworkflow
I hope that someone finds this useful, and if for any reason this is against etiquette or the rules, by all means let me know and I'll take it down.
Cheers!