as the owner of the lock you can manage permissions through the app.
Also you can apply the same argument to Lockitron. They can grant access to anyone to open your door lock and I believe you have more valuable stuff at your house.
The same argument has been applied to Lockitron... connecting physical locks to the internet is just a bad idea.
More convenient, perhaps, but now in addition to jamming a pen into the lock or cutting the chain with a pair of cutters (or whatever myriad ways to physically assault the lock that there are) you have to worry about potential software exploits enabling remote entry from anywhere in the world. It seems to me that these things are, practically by design, exponentially less secure than their purely 'analog' counterparts.
Also you can apply the same argument to Lockitron. They can grant access to anyone to open your door lock and I believe you have more valuable stuff at your house.