The key distribution is the actual problem that bitmask try to address (https://leap.se/en/docs/tech/hard-problems), it tries to make transparent the key discovery but keeping it as secure as possible. But this is still a work in progress.
Bitmask actually uses OpenVPN, just makes easy to use it securely. One summer of code has implemented support for obfsproxy (https://www.torproject.org/projects/obfsproxy.html.en), that hopefully will solve the problem in places like China.
Bitmask doesn't want to provide a proper VPN service, for the moment there is a demo service to try it. But the idea is to provide all the software easy to set up for providers, and the providers will charge you for it to sustain themselves. The nice thing of this model is that the provider only provides the service but your client comes from an independent organization, your provider can not put back doors on it.
The trust is a hard problem, we are moving the trust from the ISP to your provider (https://leap.se/en/doc/platform). Your ISP is something that you can not choose much, but on the provider you can choose or set up your own (https://leap.se/en/doc/platform).
"Only the person you send the message to can read it. Period."
To use this kind of sentences on new software not reviewed by the comunity is dangerous. There is people that risk their lifes using this kind of app.
The thing that puzzles me is that sentence:
"You can delete your message from the receivers phone."
I don't see in the 'how it works' any information about it. Do they do that in a cryptographic way somehow that I can not imagine? Or is basically that the application removes the content if the server request it, something we could avoid just with a backup or modifying the code of the app.