I can see how it would do that, and one of the things I mention when I do their surveys is the clarity of information.
I think they need to over-emphasize how the way to use the bikes is to constantly dock the bikes when you get to your destination, that way it will generally just cost you £2 a day.
I have the annual key thing and use them pretty much every day, often many times a day. I hardly ever use my own bike now, save for longer rides, and only take the tube or bus when I go outside the area served by the bikes