Hmm, well I strongly suspect that Embraer have entered into this deal with a degree of reluctance.
Had Bombardier stayed isolated, Embraer would likely have been able to compete solidly with anything coming out of Canada. With Airbus moving in on the act, due at least partly to Boeing bringing that failed trade dispute, Embraer cannot compete with that and are more or less forced to merge with Boeing.
Arguably Boeing needed Embraer more than Embraer needed Boeing, but once A+B became AirBardier there was no choice left. I fancy that Embraer's discussions with Boeing in recent months started off, "Well thanks Boeing, you've really screwed that up".