Urgency: low. no foreseen needs to pull lists by tag at the moment.
Impact to donors: none
Impact to team: if we needed to pull a specific list based on donor feedback, we wouldn't be able to do so because Zendesk won't export email addresses.
This was in Mingle: https://wikimedia.mingle.thoughtworks.com/projects/online_fundraiser/cards/1994
GR set up a tool so we could pull lists based on tags in Zendesk (i.e. bitcoin). We created one email list using this tool in August 2014, but soon after the option to do this in Civi disappeared. It used to be in the left sidebar by the unsubscribe link, and isn't any longer.
Also, it would be nice if one day we could pull lists based on keywords in Zendesk tickets. Not emergent but a nice to have.