Why use fakeroot when compiling kernel?

[Ken Januski <kenjanuski@mindspring.com>]

Thanks to all who've helped me in recompiling my kernel. I used
kernel-package on one debian box and it worked fine. But now I'm   about
to do it on another more important box and I'd like to know why I should
not do this as root, as I did on first box, and instead use fakeroot or
something similar.

I'm sure there are very good reasons. I'd just like an explanation of
the problems created by running it as root and the virtues of not doing
so. Thanks for your patience in answering a basic question.

Ken