Modern sites like to provide something with a bit more bling than just a text URL when linking to external pages. Instead, the targetted site can provide some text and graphics that should be displayed in a box that represents the link.
If people are linking to tlwebaccess or tlwebadm URLs, then it would be nice if those links look good.
One example of where this is used is when Firefox displays "Recent activity" on the new tab page. Currently, we get a scaled down version of tlwebaccess' login page, and for tlwebadm we get nothing (because of auth?).
I think Samsung Internet also uses this for the icon when sharing a page.
Safari uses this when displaying icons for "Reading list" as well. It falls back to the "apple touch icon", and then the favicon, if it isn't found.