Can someone help me understand the traffic flow with the new SmartThings integration?

I have some Samsung appliances as well as a Samsung robot vacuum with all with WiFI capability.

I’m trying to wrap my head around how device status gets updated and sent to Home Assistant when when things are configured correctly.

Do these WiFi devices report their status updates to Samsung, and since we have a custom app configured, Samsung servers also push the update to Home Assistant via the base URL we have configured?
If this is the case, is there any need for a SmartThings hub?

Or is the SmartThings hub required, and the devices will send updates to the SmartThings hub, which in turn connects with Samsung servers to report their status?

So when I’m sitting at home, and I want to start my robot vac for example, I would do that within HA, which would send the request out to Samsung servers (using the access token we generated), which would send it back to my local device? or back to a SmartThings hub (if needed)?