The biggest advantage of offsite docs is that you don't have to have the module installed to read the docs, ou can acctaully read them first, and then decide if you want to install them.
Not to mention that readign the docs for older versions of modules (or newer versions) can be very helpfull for understanding why someone else using an installation you don't have direct access to is getting different results; or to help you decide if you want to upgrade to the newest version of a distrobution.
The argument can be made "just go download the distribution and then you can read the docs locally" ... but i find that argument very silly. Why does it make more sense to ask people to download a 1MB tar.gz just to read a single POD file then to download the same documentation as a 50KB html file?
