This is a very simple way to connect your IOT devices directly ie no pc or phone. So I am surprised that the Blynk founder, I presume, aka Dmitriy, is saying nobody uses bridge. No doubt it is because it is not very well documented and people do not realise what a staggeringly brilliant feature it is (or could be if you can get it to work!)
I plan to use my photon as master and 2 cores as slaves using bridge. Hopefully I will be nobody soon!
If I can get it to work then I will get rid of my Arduino lightwave rf based security system and replace them with photons and configure a local Blynk server on a spare pc.
Blynk also has email and push notification widgets with which you can send variables and text but as with notifications seems to be limited to one per minute hence the need for a local server for a serious security application with numerous sensors, ip cameras and relays (I have mainly replaced relays with udp commands direct to IP cams for ptz etc but it doesn’t work with the old webservice2.0 dvr).