with a SpaceMouse it's easy to navigate through the Model without switching between different Mouse Actions. So, you can start measuring on one side of a wall rotate the model to the other side and continue measure. Also, you can walk/fly through the model while use the mouse to select Elements. At the End it saves a lot of Mouse clicks
iTwin.js allows an application developer to map the button assignments of a space mouse to view navigation or other functionality. The actual support for any device would need to be implemented by application its self. If you would like to see support for a specific Bentley product please submit an idea to the corresponding Bentley brand ideas portal.