Why use it?
People have been advocating hexadecimal for centuries now so what's the point of trying to convert to base42?
Well, the short answer is that this site doesn't pretend this will be anymore of a hobby than something like esperanto. So you really should not use it unless it interests you personally. Let's face it, if we can't convert the world to metric, there is little point in shifting to a different number system.
That said, base42 is very easy to grasp. If you forget the base16 component you can always reconstruct it from base4. And what better way to mess with you childs head than teach them something completely different from what all the other little kids know.
If you work with computers then base42 separates the script-kiddies from the elite.