MiniLock looks like a great option to introduce encryption to my non-technical friends. The alternative to minilock right now, for these users, is to do nothing.
Even if we do not like it, right now state of the art on file sharing (for most of the non-technical world) is an unencrypted email attachment. MiniLock looks like it might be something I can install on my mothers (non-technical) computer so that I can send her a sensitive doc (copy of my tax return, for example). This crypto system is sufficient for that use case, and the alternative is to do nothing at all. The alternatives are not GPG, or RSA, or whatever, because outside of the technical community people have no idea how to use these things.