Why is this even a question? It's a tool that someone will want to use. As long as there is a mouse, there will be tools that use it. You are essentially asking 'why does this tool exist', which is an irrelevant question and is needless negativity.
Or, put another way: think beyond your own use case before posting, yeah?
No installation required.
Your hands are going to the keyboard.
We're discussing whether or not it's worth screwing around with the mouse beforehand.