Xbox 360: Installing games, whats the point? [duplicate]
Aside from wear and tear on the disc there are performance benefits for some games (not older ones because they were made before the install technology was made available) and the benefit of saving the optical reader for your disc drive.
Most newer games will increase performance because the 360 (as with most computing products) reads quicker off a hard drive than a disc and processing it that way (assuming it's not a slow RPM drive).
You may want to read through some of the answers here as they highlight other points: Should I install Xbox 360 games to my hard drive?