My local Bank of Ireland wouldn't change Uruguayan Pesos (only 3000, about €100), "we don't do them, try 'Thomas Cook" . . anyone know off hand who might change these?
The bank are legally obliged to take legal tender, which in Ireland is Euros only (and formerly punts but they are no longer obliged to accept them).
Accepting foreign currencies is a commercial decision. For example if a currency was in rapid freefall it would be unreasonable to expect any bank to accept notes in a currency which might have fallen further by the time they are able to convert it themselves.
As this is a common method of fundraising at the airport maybe the charities have found a particular bank/institution who will do this for them (and it might not necessarily be in Ireland for the more exotic currencies)?