I personally like the scheme. But I think it caters to the technologically capable, in particular the “compose an email with this bit of magically secure content” skill.

However, these services have to accommodate the technologically less capable. So the degenerate reduction to basically “ok, we’re going to do this the hard/easy way. You just have to click where we tell you to. It’s kinda tedious, but just push the singular buttons we tell you to.”