Since the serious discussion really didn't belong in "Loony of the Week"
Things to rememember
If it connects to the internet it can be attacked
Security isn't cheap - some cheap devices have appalling security
If it can't be updated security holes can't be fixed - and there will almost certainly be security holes
If it isn't updated security won't be fixed
But on the other hand:
The privacy threat is limited by device capabilities - cameras and voice recognition are the worst (voice recognition in particular relies on sending data to a remote server for processing). If you're worried about the fridge seeing you naked don't buy a fridge with a camera. That isn't hard (are there any fridges with cameras?)
But then again:
Insecure devices can be abused to mount massive denial-of-service attacks on websites. A camera can't do much on it's own, but hundreds of thousands of them add up. A responsible person would try not to contribute to that problem.
So the advice is:
Know what you want. Don't buy a "smart" device unless you are sure that you have a use for those capabilities
Know what you are getting. You should know what it does, what data it will send over the internet and how to set it up securely
Know the manufacturer. Do they spend the effort to get security right ? Do they support their devices ? And how long for ? If (when) a security hole is found what will they do to help ? Warn you ? Provide advice to avoid or mitigate the issue ? Provide a fix ? A timely fix ?