The purpose of this is to avoid a corner case where an existing installation of Crucible is being replaced. If the old installation was not running the current code, it was possible that a new install would result in a combination of new code with an old controller image. By forcing the installer to pull the controller image this problem is avoided.
It also means that once the installer is complete that Crucible is ready to go -- there will no longer be the need to wait for the controller image to be downloaded the first time a command is run.
The purpose of this is to avoid a corner case where an existing installation of Crucible is being replaced. If the old installation was not running the current code, it was possible that a new install would result in a combination of new code with an old controller image. By forcing the installer to pull the controller image this problem is avoided.
It also means that once the installer is complete that Crucible is ready to go -- there will no longer be the need to wait for the controller image to be downloaded the first time a command is run.