What data does my dishwasher have that someone would buy?

Just by virtue of purchasing that model, I can assume a few things about your finances.

How often you use it and which cycles you use it for let me infer a few other things about other people in the house.

I can either use those to bolster confidence in a narrower profile or I can just add those data points to the raw profile and charge marketers more for either the higher confidence profile or the profile with more data points.

I'm the linked article it says that specific features of the dishwasher require an app to run. Apps can generally find out other information about you and your habits from your phone.

It's gross.

You really have to wonder if they put microphones/cameras in those to spy on you.

A camera on the INSIDE that varies the wash time based on observed soil level and stops the cycle once it sees everything is clean, now there’s an idea…

Most of the privacy issues with smart appliances has to do with the apps that you're required to use to access the smart features.

The cell phone apps harvest data. Not so much on the actual appliance. There are also issues with the apps having malware bundled in them. They're just bad apps, generally.

The appliances do get hacked though. It's not unusual for IoT devices to be used in ddos attacks.

Really, this is just a good reason that everyone should be using, at least, router level DNS filtering to disable a lot of this stuff. One can go a lot further but that's a good start.