the only thing i could see a use for this would be turning on lights to scare off the bear digging through your camp because you don't want it to know you're cowering inside the tent on Facebook with your smartphone. Other than that and showing off I don't see much use for BT switch control.
Remember BT has a range of about 35ft, and if its not connected (like say you walk out of range for a time) you have to jump into your phones setting and reconnect before you can use it. It just seems silly, why reinvent the wheel just to have a cool phone app and be hamstrung by the limitations of BT.
Especially when you've been able to do the same thing with a key fob for less than 25$ for several years now.