Mouse support has two main USES: coordinate tracking, and zooming.

鼠标支持有两个主要用途：坐标跟踪和缩放。

youdao

Full mouse support: left and right clicks, dragging, scrolling, precision pointer movement.

FORBES: Can I Access My Mac/PC Remotely From My iPhone/iPad/iPad Mini?

Oculus Rift's Tuscany demo was built with a good ol' fashioned keyboard and mouse setup in mind, but now it's unofficially scored support for motion controls.

ENGADGET

With USB support in the SmartDock, they can also use a wireless keyboard and mouse to write emails, browse and post on Facebook or watch videos from YouTube on their TV.

ENGADGET: Sony officially debuts Xperia U at MWC 2012 Mobile