It also means employees at Meldium, Heroku, and AWS (and someone who can compromise the security of any of these) has access to your passwords.

It's probably a reasonable trade for a lot of services -- I'd probably use it for an analytics dashboard, etc., but probably not for admin interfaces to do stuff to customer data (which you presumably could set up with individual user accounts and group/role management, anyway). This seems to be aimed at the ~bunch of low security passwords which are either the same across your whole business, or stored in a google docs spreadsheet now, not the most important credentials for your users.