You are invested in btct and nothing else, if the site goes away tomorrow -- they have all the direct shares and you have nothing, because buying pass thru shares is not investing in AM. Regardless of the price on btct it has zero consequence to the company.
With humility I beg to differ, security owners continue to get updated lists of share holders, so if btct goes down for whatever reason there are still accounts of who owns what. I have a lot of faith in the system Burnside set up, this may or may not prove to be misplaced, but the track record gives me a lot of confidence.