Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Most major Linux distributions use Live Disks for installation because they are a quick way to test-drive an operating system without changing a computer's setup or endangering its contents. When using a Live Disk, at worst, you may need to reset the BIOS temporarily to boot from an external device, and users have to set about deliberately to alter files on the hard drive.
Live Disks are especially handy for checking hardware support on a machine before purchasing -- assuming, that is, you can find a store clerk who knows what Live Disks are and has no fear that they might contain malware.
Another common use for Live Disks is for creating spins or remixes. Like distributions, Live Disks come and go. However, among the hundreds of Live Disks available for the download, a few especially useful Live Disks have survived for a number of years and stand out either because of their basic functionality or their selection of applications: