If your normal operating environment is Windows 98 or later, then you can install the AF version of WinUAE, complete with supporting files, onto your HD and start it from Windows any time.
If your normal operating environment is Linux, you can install the Linux version of UAE and either copy the supporting files from the CD or let them be loaded from the CD (adjust the configuration in .uaerc appropriately.)
I can't say what the answer is for Mac systems.
Yes, the CD is directly bootable on some hardware. It doesn't boot on my Intel PC, though, apparently because of some deficiency in Knoppix Linux with respect to my hardware. Since I already run Slackware, I just installed UAE on my Slackware and run it from there, letting it find its needed files on the CD.
The value of the Amiga Forever CD, in my opinion, is largely in the Amiga files (kickstart images, utilities, etc.) that are all provided together, conveniently in one place, rather than in the bootable Knoppix environment.
