It absolutely was introduced as a safety measure for kids and pets. The safety of the electronics seems like more of a myth. I don't remember any Tesla announcement about it. Links for that?
Here's the article with the release notes for Cabin Overheat Protection:
Tesla v8.0 software update is being pushed right now, all the details and full release notes - Electrek
"
Cabin Overheat Protection
In an industry-first safety measure, we’re also introducing Cabin Overheat Protect, focused on child (and pet) safety. This feature keeps the car at a safe temperature for hours, even when the car is off. This feature is only made possible by an electric vehicle with Tesla’s uniquely large battery packs."