The advantages of maintaining lists like these on a website lie in the factors we might label inclusivity, accessibility and updateability.

While print journals and other traditional resources can provide a list of both print and electronic resources, a website can provide that same list with physical links  to the latter. So the two media have approximately equivalent abilities to include; the website increases the ability to access.

As for the ability to update frequently and consistently: a journal, mired in a quarterly (or even less frequent) publication cycle, must often wait months to update a published list. A website is limited only by the frequency with which those maintaining it are able to make changes.

The benefits of the accessibility/updateability issues are reflected in the adopted practice of electronic journals, such as Kairos,  of maintaining a site linking to other resources of interest.