Then again, do you need security updates on your ereader? Are you really going to log in to your email, bank account, or whatever other service on a screen that does 15FPS (and is one of the best eink displays at that)?
I mean, what for? Sure, synchronizing books, yeah. I do that, then turn the wifi off. It's just draining battery for no reason. Perhaps synchronizing your notes to the cloud if you use the ereader as a tablet, that I could see for heavy note takers.