Where I live for the United States obviously Dublin is used but if people are going to Australia or Dubai alot of people will just fly to England and connect there. It's more convenient.
Not sure where you live but BFS already has a direct link to the US
And there are plenty of connection options for westbound too.... but yes, that said a significant number of NI travellers are still using Dublin going to the US, presumably largely for cost reasons?
Yes I agree it makes little sense going east, where there are a lot of convenient connecting options that will bring NI pax back to their local airport (one or other of them)