as we learn time and time again with this kind of thing, the scary things don't come from the data and metrics that they want, the scary things come as a form of collateral damage that occurs when the company does whatever they have to do in order to harvest the metrics that they're interested in.
Here's a devils' advocate leap that isn't too far from the realities of IoT devices: Company X's telemetry function is broken, allowing arbitrary remote code execution. The IoT device receives a command that causes property or personal damage -- or it becomes a node in a much larger destructive network.
These things happen when features get packed in faster than the security can follow.
Yeah, yeah, the Weber product is just a thermometer. It can still be a node in a malicious network, given attacker incentive.
This is a poor example -- it's an interface that accepted and expected inputs -- but I think it serves as a good example of IoT doing security wrong.
https://www.wired.com/story/snoo-smart-bassinet-vulnerabilit...
Now imagine what could be inferred from your meat grilling data.
I am not saying that that people go around doing nefarious things with your meat grilling data. In fact, there is a very good chance that it is not even being collected. Yet we live in a world that is hungry for data of virtually any type and in any form, which makes both data collection and nefariousness a possibility when that data is being handled by an Internet connected device. Personally, I find that possibility creepy - even if no harm is being done.
In other words - the backlash over excessive data storage and retention is very much good thing, but let's be careful to try keep things in perspective a bit. Otherwise we run the risk of people not taking us seriously when it actually matters.