Many people here, including me, use Harmony. 
For many different things.
This is the basic FAQ (this is a clickable link)
Some people just use smartthings to trigger harmony activities from motion sensors or something like that.
Other people mix together home automation devices and entertainment devices, so when it’s movie night the curtains close, the lights dim, the A/V stuff comes on.
Some people use the harmony button remote to toggle their lights on and off.
It’s a two-way integration. You can start things from the harmony side or the smart thing side.
However, it’s always through the concept of harmony activities.
Was there something in particular you were interested in doing?