Ask HN: What Is IoT Security?

I've been hearing a lot of buzzwords around IoT security and I'm still trying to understand what the big deal is. Let's take the following situation.

Say I have a raspberry pi on my home network that has only one function: Every hour it performs a GET request to https://www.myapi.com/time and gets a JSON response back (current date) and maybe reads out loud through a speaker.

If the device has all inbound ports blocked (so no SSH), communicates using TLS 1.2 to my trusted web server, and has updates and other connectivity turned off, what is the inherent risk? Other than if at some point my version of TLS becomes outdated.