Makes things much easier to search for too, as those IDs don't need to change across languages or UI refreshes (which may e.g. rewrite the error messages, break

Makes things much easier to search for too, as those IDs don't need to change across languages or UI refreshes (which may e.g. rewrite the error messages, breaking all those old searchable phrases), both internally (unambiguous to grep!) and externally (google / stackoverflow / etc). And users are FAR more likely to read them back correctly to support, instead of saying what they think the message says (every tech-support-person has had to deal with this some number of times). Error IDs on everything, please.