The Oxford English Dictionary tracks the term mouse pad to the 25 August, 1983, publication of InfoWorld, and the predominantly British term mousemat http://www.a1imaging.com/ to 17 October, 1989, in the publication 3D.
The three most important benefits of the introduction of the mousepad were exceptional speed, more precision, and enjoyment for the user. A secondary benefit was keeping the desk or table surface from being scratched and worn by continuous hand and mouse rubbing motion. Another benefit was reduction of the collection of debris under the mouse, which resulted in reduced jitter of the pointer on the display.