Not really. It would be like mailing a letter, to the person standing right next to you.
Now if the bluetooth range had a greater range then I would say this app had some uses. For instance, if you were trying to find out which home circuit breaker flipped off the power to a specific circuit and needed someone inside the house to tell you if power to a device went out. Or if you were out in the garage and back inside the house your wife wanted to let you know dinner was ready.
Anyway I see this app is no longer free and now costs $.99, now it certainly is not worth it.