This is interesting, but I think they make some incorrect assumptions. For instance, people won't use Evernote for most stuff, and then a more-secure app for specific things -- they'll either use Evernote and accept the security weakness, for everything, or find something marginally less easy to use or more expensive, but much more secure, and use that for everything. The issue is exactly how much less easy to use vs. how much more secure, and how much users care about each.