My reason for asking is because I don't want my Minecraft Xbox 360 Edition playthrough to be stopped, and I don't really want ANY of my saves to be deleted at all.
As a general rule, your worlds should be fine. That said, there has been one report so far of this update (and several with previous updates) causing a world to reset/corrupt. It's not a frequent thing/bug, but it can happen. Best move is to backup your world gamesave files to another device (e.g. USB stick) before accepting the update. That way, if it does happen, you should be able to copy your backup file back onto your hard drive and try to launch it again.
Minecraft is a spicy meme
