together with the post 45, it can be assumed:
it is a system level application
it does have closed, obfuscated code
it did not passed any external audit*
it does contain some controversial sentences in T&Cs
* - perhaps as the result of being written by a single person (in theory - we cannot know if there is someone behind)
Now it is each user individual choice: use it or not. If you do trust the developer, "do not have anything to hide" - feel free to use it.
Personally, if I'd be interested then yes: I would use it. After setting it up on a dummy old phone for a month and checking traffic very carefully. single encrypted packet would eliminate it from use.
But again, it is a personal choice of each individual user to give access to all and any private information stored and obtained by the phone (voice, video recording capabilities are obvious) to the developer who does not trust the users enough to deobfuscate/open the code.
It is just a mutual trust: you trust them as much as they trust you, isn't it?