I actually find it very nice to get notifications about my toaster oven being preheated or done cooking, or being able to see how much time is left or remotely stop it.
I can totally see a point in some of the features.
The other day my wife and I got 20 minutes from home before I said "oh shit I don't know if I turned the oven off". Turns out I did, but we had to drive home to check. I would have loved to pull up an app that told me it was actually off, or even if I was on be able to turn it off from there.
With that said, it's not worth all the extra bullshit in my opinion.
That's always a possibility especially when every company under the sun is making smart things on a whim for as cheap as possible. I don't trust any of them as far as I can throw an oven.
I have a few random smart things, but before I connect them to the internet I make sure they have a decent api that I can use, block external access from the router and set up a little interface so that I can VPN into my home and control stuff if I need to. So in order for anything to be compromised my whole network would have to be owned. Which is still possible but I trust that a lot more than letting 20 different apps for each device have access to anything in my home.