Why would an oven need Internet access? You physically need to open the oven and put stuff in it and then take it out. Food over IP is not a thing yet.
Unless it has an internal camera with which you can observe the food while it's cooking, I see no advantage of using an Internet connected oven.
I'm against stuff like this and totally eschew even offline gadgets, but its not that hard to come up with some use cases.
After you left the house: "Did I turn off the oven? Did I turn off a burner (eg slowly cooking a bean bot)?" Now you can know.
Is a (top or interior or anywhere) burner slowly leaking and should alert the owner? Maybe.
And as you said, pre-heating, though this is actually a feature that makes things more dangerous! If you or someone else was temporarily storing something not-ovenable in the oven and pre-heated remotely, you could come home to something very bad.
I'd much rather have the oven connect to a physical device on my home LAN instead, which I could then access through a web interface with a tunneled port or whatever. Same with security cameras, smart lightbulbs, etc. None of this stuff should ever be connecting to the Internet directly.
I wouldn't mind having "read-only" or "make-safe" functionality: in addition to "Did I turn off the oven?" above, things like timer and burner status would be nice.
A "Turn off oven NOW" button on an app would be an example of "make-safe". Worst case situation is that your dinner is undercooked.
Maybe they're preparing for a ST:TNG future where you can use an app to tell your food replicator to make tea, Earl Grey, hot while you're arriving home.
Interesting those are totally valid use cases but I would NEVER use those through a vendor specific app/cloud. Only locally connected to Home Assistant or something like that via MQTT or some other protocol. I wouldn't want someone from the outside turning my oven on or worse, start the super hot cleaning cycle when I don't expect it the same way I wouldn't want someone having control over my front door or garage.
So Frigidaire, or whoever, can sell data about how and when you use your oven. Maybe this info will be used to show you ads for turkeys on your phone, or even on the oven if future versions have screens.
If one's life is such a blur that they can't wait the 20 min it takes to preheat the oven, with the risks that comes with (is there something already in there that you don't know about, like a flammable cleanser, etc.) then I dunno. I think they can find other things in their lives much more useful.
All potentially lethal/flammable objects in your household would probably benefit from some kind of remote monitoring capability, assuming you can do that securely.
Many fancy ovens have temperature probes which relate to cooking profiles you can use as well. Being able to actually look at a glance how the roast is doing would be nice. Sure, one could also do this with another device, but having it all integrated is cool.
not a internet thing, but some Jenn Air ovens had (and maybe still have) a "sabbath mode". Observant Jews would prepare their Saturday dinner, place it in the oven before sundown on Friday, then the oven would turn iself on sometime on Saturday afternoon to begin to cook the food so it would be ready at sundown on Saturday.
A similar use could be used for internet connectivity. not for people skirting sabbath rules, but someone that has the turkey in the oven but doesn't know when exactly they'll get home to eat, but want to start baking it while you're away. Not saying that is a likely of common need, but it could happen.
i have jenn air appliances and tried to connect to my dishwasher solely because i was curious as to why anyone would want their dishwasher to be connected to the internet. i could never get it to actually work, so i am still in the dark as to what i am missing out on in the world of internet connected dishwashers.
Unless it has an internal camera with which you can observe the food while it's cooking, I see no advantage of using an Internet connected oven.
edit: okay, preheat, fair - that's actually useful