Another use for a large swap partition is if you want to put /tmp into tmpfs.
Whether doing so is a "good thing(TM)" is a religious debate that I don't want to stir up here. But there are people who do it, and for them a large swap partition can be useful.
RickPS: We haven't heard back from the OP yet. I'm with the folks who think he probably forgot to put it in fstab, but we won't know until he replies.