If you can handle all the infrastructure on your own, for example, setting up the database, installing the OS and any software packages needed by your app then there is no need to give anyone access. In fact, I would suspect if someone requests it. If you can't handle the infrastructure 100% on your own then it makes sense for someone to do it for you (or to guide you, at least).
From a developer point of view, when I work on a custom plugin I always setup a demo server on my own so that we avoid these kind of issues.