It only works for comparatively small packages, you'll need to keep an eye out yourself for security patches -- but it allows you to install stuff via dpkg -- and generally if the thing is too complex, you'll probably want to run a distribution package anyway (something simple in this context is nginx, varnish, nodejs (but I tend to run upstream nodejs -- too much of a moving target...) -- something complex might be pygame or network-manager -- basically stuff that has deep and wide dependencies.

For stuff that I need to get from upstream, I try to use xstow -- it's a great way to keep either /usr/local or ~/opt/ manageable. Note: for nodejs -- it doesn't read the prefix variable for just make install, use DESTDIR (and do some manual cleanup):

http://www.debian-administration.org/articles/682#comment_26