This is a really interesting discussion.
If sacrifice is giving up something when there is no benefit for you in it (For example, the ones Rainbow listed, Neal giving up his life so that Zelena’s identity could be revealed, Rumple giving up his life to stop Pan, Regina giving up Henry to save everyone from Pan’s curse), and a trade is giving up something you like for something you like even more, for example, Emma swapping New York for Storybrooke, where exactly on that scale would Hook giving up the JR for Emma fall?
On the one hand, Hook stood to benefit. He gives up the JR and Emma likes him more. However, on the other hand, Hook didn’t know how Emma would feel about him. He could’ve given up his ship for nothing and he certainly wasn’t trying to shove what he did in Emma’s face. Since Hook did not know the outcome that giving up the JR would result in, is it a sacrifice or not?
All magic comes with a price!
Keeper of Felix