200 is more than the connecting A320 can hold, assuming it's not an A319 (!) That's also the majority of seats on a B777. Seems like a one off if true.
Btw aside from TPA and LAS, eveything else going West is in the Caribbean so not going to have an impact on US flights.
Why would I be staggered? They're offering good connections on their own metal from across Europe, DY do connections, EZY don't. Flip that one then, if they have to fill them using feed on a loco model, does DU or DY get the benefit of the revenue?