I was watching a computer user the other day, typing, stopping typing, grabbing the mouse, highlighting text, moving the mouse, right clicking, choosing paste from the pop up menu and then putting hands back to the keyboard to keep typing.
Now, let it be said that when it comes to computers there are generally two or three ways to accomplish any task.
If the mouse works for you, great, stick with it. But if you are a fast typer and your hands are already on the keyboard, you can simply hold down your shift key and use your keyboard arrows up and down or left and right and highlight text. Once highlighted, CTRL+C results in a copy, and CTRL+V results in a paste, of your highlighted selection.
Quick and easy when you are in a bind.
By the way, why is it CTRL+V instead of CTRL+P?
One theory is that CTRL+P had already been designated as a shortcut for PRINT so it was already taken.