Great for those who have existing switches in place that they want to keep. For instance, custom switches or those with fancy wall plate/switch plate covers. This allows you to put a small module “the size of two Oreos” behind the switch and allow them to act as both smart and dumb switches. Controls two devices in the same time. Shelly 2.5 does not offer dimming functionality however other products in the Shelly lineup do. Provides REST API and MQTT compatibility for those looking to tinker. Other models are available that monitor power consumption, don’t require neutral lines, provide lighting effects, extended energy management features, and more.
Newer versions are UL certified which provides added comfort on fire safety vs. the Sonoff models. Keep this in mind when ordering from Amazon in case you are sent a model from an older batch that is not UL certified. Read this for more comparison between Shelly vs. Sonoff.