The primary use case is getting access to various test machines from one location.
AirTies makes smart WiFi technology which end up in people's homes. I set it up in a house with WiFi devices. We test our Extenders and gateways with a bunch of clients using TeamViewer. I can access the clients to view the data being collected or what's connecting to wired ports. I do this locally, and sometimes, I access the home office in Istanbul.
It is used on a mix of Mac and Windows machines. Even though we have Android and iOS devices to test for WiFi devices, we haven't put TeamViewer on them yet.
We have a lot of IOT devices, but we haven't used TeamViewer that much manage them or get to them. While I'm open to it, I'm not sure of the roadmap for the rest of the QA team.