[dave78]

There are plenty of IoT devices that people want to execute commands on (anything remotely controlled, basically). Polling for commands on a periodic basis introduces lag into that process which is irritating. Furthermore, polling at a frequent interval can end up using a lot of power as well versus waiting in a receive-only mode for an incoming command.

[raggi]

The alternative to polling is unfortunately polling, which is what the article is about.

You can avoid polling for messages, but you have to send packets outbound regularly in order to maintain a NAT mapping & connection, so that the external side can send messages inward.

The latency is overcome this way, so latency is a solvable problem, but this need to constantly wake up a radio every <30s in order to keep a NAT session alive is a significant power draw.

In theory you might be able to avoid this with NAT-PMP / UPnP however their deployments are inconsistent and their server side implementations are extremely buggy.